When using a File BC, and the Inbound Part in the File WSDL is based on a XSD in
which elementFormDefault’s value is “qualified”. In this case, when a leaf node
of this XSD is mapped in the BPEL Mapper, the XPath query is generated with
namespace prefixes.
But the XPath query failed during execution. We had to workaroud this by
removing the namespace prefixes. To explain in more detail, when the mapping was
done in the Design view of the BPEL Mapper, the <copy> structure looked like this - 

-------------------------------
<copy>
<from>$FileOperationIn.InboundPartForFile/ns0:BorrowerInformation/ns0:SocialSecurityNumber</from>
<to>$GetAccountInformationIn.parameters/ns3:ssn</to>
</copy>
-------------------------------

As a workaround, I changed the <copy> structure to this

-------------------------------
<copy>
<from>$FileOperationIn.InboundPartForFile/BorrowerInformation/SocialSecurityNumber</from>
<to>$GetAccountInformationIn.parameters/ssn</to>
</copy>
-------------------------------

- and that worked. I discussed this with Murali and he suggested that it appears
that the DOM supplied by File BC seems to be not-namespace-aware.