Execute Value Mapping into XSLT

Hi experts,

I'm executing an XSLT mapping where I need to get the user from a value mapping I've previusly created.

This is my XSLT:

<?xml version="1.0" encoding="UTF-8"?>

<ns0:stylesheet version="1.0" xmlns:ns0="http://www.w3.org/1999/XSL/Transform" xmlns:trg="http://comsol-ag.com/xi/rfcxslt" xmlns:ns1="http://test/xi/tsts" xmlns:ValueMap="java:com.sap.aii.mapping.value.api.XIVMService">

<ns0:template match="/">

<ns1:Envelope xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns1="http://schemas.xmlsoap.org/soap/envelope/">

<ns1:Header>

<ns2:ServiceAuthHeader xmlns:ns2="http://test.webservice.it/">

<ns0:variable name="User" select="ValueMap:executeMapping('http://sap.com/xi/XI/SUPPLIERPORTAL','SP','USER','USER','http://sap.com/xi/XI/SUPPLIERPORTAL','SP','USER')"/>

<ns2:Username>

<ns0:value-of select="$User"/>

</ns2:Username>

<ns2:Password>1234</ns2:Password>

</ns2:ServiceAuthHeader>

</ns1:Header>

<ns1:Body>

<ns0:copy-of select="*"/>

</ns1:Body>

</ns1:Envelope>

</ns0:template>

</ns0:stylesheet>

This is my Value Mapping:

Context: http://sap.com/xi/XI/SUPPLIERPORTAL

Agency

Schema

Value

And this is the error:

Transformer Configuration Exception occurred when loading XSLT AddUserPass_v3.xsl;

details: The first argument to the non-static Java function
'executeMapping' is not a valid object reference.

See error logs

for details

It seems that the error is in the first argument, but it is the context and it is correct.

Any ideas?

Thanks a lot.