How to call a SAP service from adobe flex

Hi experts,
I need to call a webservice create from SAP BAPI  my URL is: http://xxxxxxxxx:8000/sap/bc/srt/wsdl/bndg_DD90E166ACE1B1F18AD8001B789FF0AD/wsdl11/allinone/ws_policy/document?sap-client=200, with this URL I can test the webservice from WsNavigator.
The operation is ZimrfcVerifOtUbica and the input structure is:
> PiNumeroAlmacen (input parameter)
> PiOTransporte (input parameter)
The output structure is:
>PoMessage (output parameter)
I've created a view with two inputfield (one to PiNumeroAlmacen, one to PiOTransporte), one button and one label (to put the result value).
but I don't know how to call the WS, I tried with this code:
<mx:WebService id="ZCCONVERTERService"
     wsdl="http://xxxxxxxxx:8000/sap/bc/srt/wsdl/bndg_DD90E166ACE1B1F18AD8001B789FF0AD/wsdl11/allinone/ws_policy/document?sap-client=200;" useProxy="false" >
          <mx:operation name="ZimrfcVerifOtUbica" resultFormat="e4x">
               <mx:request >
          </mx:operation >
and I get this error: [RPC Fault faultString="Could not load WSDL" faultCode="Server.NoServicesInWSDL" faultDetail="No <wsdl:service> elements found in WSDL at ."].
I tried with actionscript and runtime library but I get this error: java.lang.Exception: Unsupported element in WSDL file: UnknownExtensibilityElement
I tried put in Data--> Import Web Service and I put the URL and I get Unable to load the WSDL.  Specify another URI.
Other thing is for this webservice I've created a logic destination, and this webservice is used in a webdynpro aplication and works correctly. But now I need to use the same webservice in flex.
Could you help me to call to this webservice?
Thanks in advance.


I have could do it, but now I'm trying to do the same with a SAP standard service.
Any idea?