NWDS adding prefix without namespace

Hi,

I'm facing an issue with a prefix without namespace.

I'm calling a webservice defined on XI from EP through a Service built in NWDS.

<?xml version="1.0" encoding="utf-8"?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:wn3="http://www.w3.org/1999/XMLSchema" xmlns:wn2="http://www.w3.org/2000/10/XMLSchema" xmlns:wn1="http://www.w3.org/2001/XMLSchema" x ... "http://www.w3.org/2001/XMLSchema-instance" xmlns:wn4="http://iwaysoftware.com/iwaf/XI/System" xmlns:tns="http://iwaysoftware.com/iwaf/XI/System">

<SOAP-ENV:Body>
<wn4:EPSiebelActionMT>
<prt0:select/>
</wn4:EPSiebelActionMT>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>

Prefix 'prt0' is not mapped to a namespace but is added to the <select> node.

The call to XI leads to an error since XI seems to dislike undefined prefix.

What should be done ?

Thx,

mejj