Escape characters in XML msg from WM to Siebel


I’m currently sending messages from the XML adapter of webmethods to a business process running on the siebel web engine (through IIS).
When there is an escape character in the XML, for instance: & the xml that comes in on Siebel is cut short. For instance I sent:
beer & wine

Siebel receives:

Has anyone an idea of why this is and how this can be solved?

WM enterprise 5.0.1 running on Solaris, XML adapter 4.2 on windows NT4 and Siebel 6.4 on the same NT machine as the adapter.

kind regards