União no SQL ao criar arquivo XML

Eu tive algum problema com minha consulta SQL, que cria um arquivo XML. eu quero fazerUNION esta consulta, mas não funciona.

(SELECT 1 AS "ns0:kindOfItem",
code AS "ns0:wholeCode",
REPLACE(weight, ',', '.') AS "ns0:weight",
1 AS "ns0:ammountOfNumbers",
(SELECT price AS "ns0:value",
'EUR' as "ns0:currency"
FOR XML PATH ('ns0:sendedItems'), TYPE),
(SELECT 
'EUR' as "ns0:currency"
FOR XML PATH ('ns0:present'), TYPE)
FROM [PL].[dbo].[dk_documents] where id in (1,2,3)
FOR XML PATH('test'))

Esta consulta funciona bem, mas quando tento fazerUNION como aqui:

(SELECT 1 AS "ns0:kindOfItem",
code AS "ns0:wholeCode",
REPLACE(weight, ',', '.') AS "ns0:weight",
1 AS "ns0:ammountOfNumbers",
(SELECT price AS "ns0:value",
'EUR' as "ns0:currency"
FOR XML PATH ('ns0:sendedItems'), TYPE),
(SELECT 
'EUR' as "ns0:currency"
FOR XML PATH ('ns0:present'), TYPE)
FROM [PL].[dbo].[dk_documents] where id in (1,2,3)

UNION

(SELECT 1 AS "ns0:kindOfItem",
code AS "ns0:wholeCode",
REPLACE(weight, ',', '.') AS "ns0:weight",
1 AS "ns0:ammountOfNumbers",
(SELECT price AS "ns0:value",
'EUR' as "ns0:currency"
FOR XML PATH ('ns0:sendedItems'), TYPE),
(SELECT 
'EUR' as "ns0:currency"
FOR XML PATH ('ns0:present'), TYPE)
FROM [PL2].[dbo].[dk_documents] where id in (1,2,3)
FOR XML PATH('test'))

Esta consulta me deu um erro:

O tipo de dados xml não pode ser usado como um operando para os operadores UNION, INTERSECT ou EXCEPT porque não é comparável.