Tengo el siguiente estilo definido en mi Diccionario de recursos:

<!-- ListViewItem Styles-->
<LinearGradientBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" StartPoint="0,0" EndPoint="0,1">
    <LinearGradientBrush.GradientStops>
        <GradientStopCollection>
            <GradientStop Color="#F7D073" Offset="0"/>
            <GradientStop Color="#F1A62F" Offset="1"/>
        </GradientStopCollection>
    </LinearGradientBrush.GradientStops>
</LinearGradientBrush>

<LinearGradientBrush x:Key="{x:Static SystemColors.ControlBrushKey}" StartPoint="0,0" EndPoint="0,1">
    <LinearGradientBrush.GradientStops>
        <GradientStopCollection>
            <GradientStop Color="#F7D073" Offset="0"/>
            <GradientStop Color="#F1A62F" Offset="1"/>
        </GradientStopCollection>
    </LinearGradientBrush.GradientStops>
</LinearGradientBrush>

<LinearGradientBrush x:Key="MouseOverBrush" StartPoint="0,0" EndPoint="0,1">
    <LinearGradientBrush.GradientStops>
        <GradientStopCollection>
            <GradientStop Color="#E4F0FD" Offset="0"/>
            <GradientStop Color="#D7EAFD" Offset="1"/>
        </GradientStopCollection>
    </LinearGradientBrush.GradientStops>
</LinearGradientBrush>

<Style TargetType="{x:Type ListViewItem}">
    <Setter Property="Foreground" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataForeground, Converter={StaticResource ColorToBrushConverter}}" />
    <Setter Property="Padding" Value="1,0,1,0" />
    <Setter Property="FontWeight" Value="Normal" />
    <Setter Property="BorderThickness" Value="1"/>
    <Setter Property="BorderBrush" Value="Transparent"/>
    <Style.Triggers>
        <Trigger Property="IsMouseOver" Value="true">
            <Setter Property="Background" Value="{StaticResource MouseOverBrush}" />
            <Setter Property="BorderBrush" Value="#C6E1FC" />
            <Setter Property="BorderThickness" Value="1" />
        </Trigger>
        <Trigger Property="IsSelected" Value="True">
            <Setter Property="Foreground" Value="Black" />
            <Setter Property="BorderBrush" Value="#909090" />
            <Setter Property="BorderThickness" Value="1" />
        </Trigger>
    </Style.Triggers>
    <Style.Resources>
        <Style TargetType="Border">
            <Setter Property="CornerRadius" Value="2"/>
        </Style>
    </Style.Resources>
</Style>
<!-- /ListViewItem Styles-->

Cuando estaba usando Windows XP, el comportamiento que estaba obteniendo era que mis gradientes se usaban para Hightlight y la selección. Ahora he cambiado a usar Windows 7 y parece que los degradados ya no se usan, los colores de resaltado / selección ahora son el azul claro del aspecto VS.

Cualquier sugerencia sobre por qué sucedería esto y cómo lo soluciono de tal manera que funcione igual en Windows XP y Windows 7 (tenemos un entorno multiplataforma)

Gracias

Solución completa después de los comentarios

<LinearGradientBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" StartPoint="0,0" EndPoint="0,1">
    <LinearGradientBrush.GradientStops>
        <GradientStopCollection>
            <GradientStop Color="#F7D073" Offset="0"/>
            <GradientStop Color="#F1A62F" Offset="1"/>
        </GradientStopCollection>
    </LinearGradientBrush.GradientStops>
</LinearGradientBrush>

<LinearGradientBrush x:Key="{x:Static SystemColors.ControlBrushKey}" StartPoint="0,0" EndPoint="0,1">
    <LinearGradientBrush.GradientStops>
        <GradientStopCollection>
            <GradientStop Color="#F7D073" Offset="0"/>
            <GradientStop Color="#F1A62F" Offset="1"/>
        </GradientStopCollection>
    </LinearGradientBrush.GradientStops>
</LinearGradientBrush>

<LinearGradientBrush x:Key="MouseOverBrush" StartPoint="0,0" EndPoint="0,1">
    <LinearGradientBrush.GradientStops>
        <GradientStopCollection>
            <GradientStop Color="#E4F0FD" Offset="0"/>
            <GradientStop Color="#D7EAFD" Offset="1"/>
        </GradientStopCollection>
    </LinearGradientBrush.GradientStops>
</LinearGradientBrush>

<Style TargetType="{x:Type ListViewItem}">
    <Setter Property="Foreground" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataForeground, Converter={StaticResource ColorToBrushConverter}}" />
    <Setter Property="Padding" Value="1,0,1,0" />
    <Setter Property="FontWeight" Value="Normal" />
    <Setter Property="BorderThickness" Value="1"/>
    <Setter Property="BorderBrush" Value="Transparent"/>
    <Style.Triggers>
        <Trigger Property="IsMouseOver" Value="true">
            <Setter Property="Background" Value="{StaticResource MouseOverBrush}" />
            <Setter Property="BorderBrush" Value="#C6E1FC" />
            <Setter Property="BorderThickness" Value="1" />
        </Trigger>
        <Trigger Property="IsSelected" Value="True">
            <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
            <Setter Property="Foreground" Value="Black" />
            <Setter Property="BorderBrush" Value="#909090" />
            <Setter Property="BorderThickness" Value="1" />
        </Trigger>
        <!-- This part of the triger is for when Windows Aero theme is turned on Win Vista/7-->
        <MultiDataTrigger>
            <MultiDataTrigger.Conditions>
                <Condition Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ListViewItem}, Path=IsSelected}" Value="True" />
                <Condition Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ListView}, Path=IsKeyboardFocusWithin}" Value="True" />
            </MultiDataTrigger.Conditions>
            <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
            <Setter Property="Foreground" Value="Black" />
            <Setter Property="BorderBrush" Value="#909090" />
            <Setter Property="BorderThickness" Value="1" />
        </MultiDataTrigger>
        <MultiDataTrigger>
            <MultiDataTrigger.Conditions>
                <Condition Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ListViewItem}, Path=IsSelected}" Value="True" />
                <Condition Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ListView}, Path=IsKeyboardFocusWithin}" Value="False" />
            </MultiDataTrigger.Conditions>
            <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
            <Setter Property="Foreground" Value="Black" />
            <Setter Property="BorderBrush" Value="#909090" />
            <Setter Property="BorderThickness" Value="1" />
        </MultiDataTrigger>
    </Style.Triggers>
    <Style.Resources>
        <Style TargetType="Border">
            <Setter Property="CornerRadius" Value="2"/>
        </Style>
    </Style.Resources>
</Style>