Estoy creando a continuación el procedimiento almacenado.

declare @PageNum as Int
declare @PerPageResult as Int
declare @StartDate as varchar(25)
declare @EndDate as varchar(25)
declare @SortType as Varchar(50)
declare @SortDirection as Varchar(4)
set @PageNum=1
set @PerPageResult=20
set @StartDate='2008-02-08'
set @EndDate='2015-02-08'
set @SortType='RegDate'
set @SortDirection='Desc'
declare @Temp Table(RowNum int, RegDate Date, Registered int, Female int, Male int, [Join] int, Rebill int, TotalPointsEarned int, Expire int)
declare @sort varchar(50)
Insert into @Temp
    Select ROW_NUMBER() over (order by @SortType+' '+@SortDirection) As RowNum, * From (    
    SELECT 
    CAST(m.registrationdate AS Date) as RegDate,    
    count(m.id) Registered,
    count(CASE WHEN m.gender='F' then 'F' end) As Female,
    count(CASE WHEN m.gender='M' then 'M' end) As Male
    count(CASE WHEN p.paymenttransactiontype='N' then 'N' end) As [Join],
    count(CASE WHEN p.paymenttransactiontype='R' then 'R' end) As Rebill,
    count(m.tokensearned) As TotalPointsEarned,
    count(CASE WHEN p.paymenttransactiontype='E' then 'E' end) As Expire
    from member m
    join payment p on m.id=p.id_member
    join user_role u on u.member_id=m.id
    where u.role_id <> 3
    and CAST(m.registrationdate AS Date) > @StartDate and CAST(m.registrationdate AS Date) < @EndDate
    GROUP BY CAST(m.registrationdate AS Date)
    ) as aa 
    Select * from @Temp Where RowNum>((@PageNum-1)*@PerPageResult) and RowNum<=@PerPageResult * @PageNum
    Order by @SortType+' '+@SortDirection

En lo de arriba cuando paso elOrder by cláusula dinámicamente, no ordena los datos correctamente, pero cuando escribo el nombre de la columna explícitamente, funciona bien. Podría ser su toma@SortType+' '+@SortDirection comovarchar más bien queDate

Intenté escribirOrder by case when (@Sort='RegDate' and @SortDirection='Desc') Then RegDate End Desc, pero no funcionó

¿Cómo puedo pasar orden por dinámicamente aquí.

Editar: @Andomar: probé la solución provista y agregué un campo más para el tipo de fecha. Y tampoco funcionó.

A continuación es lo que hice.

create table t1 (id int, name varchar(50), dt date);
insert t1 values 
    (1, 'Chihiro Ogino','2009-02-08'), 
    (2, 'Spirit of the Kohaku River','2008-02-08'), 
    (3, 'Yubaba','2012-02-08');



declare @sortColumn varchar(50) = 'dt'
declare @sortOrder varchar(50) = 'ASC'

select  *
from    t1
order by
        case
        when @sortOrder <> 'ASC' then 0
        when @sortColumn = 'id' then id
        end ASC
,       case
        when @sortOrder <> 'ASC' then ''
        when @sortColumn = 'name' then name
        end ASC
,       case
        when @sortOrder <> 'ASC' then ''
        when @sortColumn = 'dt' then name
        end ASC
,       case
        when @sortOrder <> 'DESC' then 0
        when @sortColumn = 'id' then id
        end DESC
,       case
        when @sortOrder <> 'DESC' then ''
        when @sortColumn = 'name' then name
        end DESC
,       case
        when @sortOrder <> 'DESC' then ''
        when @sortColumn = 'dt' then name
        end DESC