soapui HTTP Monitor Tunnel does not deliver ?wsdl GET

soapui HTTP Monitor Tunnel does not deliver the wsdl when i send a GET request to the service Endpoint with the Parameter ?wsdl

Instead of the ?wsdl i see null in the client response:

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"><soap:Body><soap:Fault><faultcode>soap:Server</faultcode><faultstring>No such operation: null (HTTP GET PATH_INFO: /omiservice20/soap/OmiFreenetServicenull)</faultstring></soap:Fault></soap:Body></soap:Envelope>

In the HTTP Monitor the request looks fine, but it apperently becomes modified during interception by the SOAP UI HTTP Monitor Tunnel:

>>>Request RAW
GET /myService/soap/MyService?wsdl HTTP/1.1
Host: somehost.de
Authorization: Basic Og==
X-Forwarded-For: 194.98.157.210
X-Forwarded-Host: 194.98.157.212
X-Forwarded-Server: 194.98.157.212
Connection: Keep-Alive


>>>>Response RAW
HTTP/1.1 200 
Server: Apache-Coyote/1.1
Content-Type: text/xml;charset=UTF-8
Content-Length: 281
Date: Thu, 10 May 2012 08:06:46 GMT
Connection: close

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
   <soap:Body>
      <soap:Fault>
         <faultcode>soap:Server</faultcode>
         <faultstring>No such operation: null (HTTP GET PATH_INFO: /myService/soap/MyServicenull)</faultstring>
      </soap:Fault>
   </soap:Body>
</soap:Envelope>