Web Service method calls having "?wsdl" at the end of the URL

Issue

• The way our webservice gets called is first we connect to the remote port with the URL ?wsdl at the end, e.g. ../sopsSimWs/SopsSubscriptionPortingImpl?wsdl.
• And then make the webservice method call is made on that port object. These two calls are translated as following on the remote system consecutively, both of which has "?wsdl" at the end of the URL:-

192.168.0.210 - - [26/Jun/2013:14:38:19 -0400] "GET /xxxxx/SopsSubscriptionPortingImpl?wsdl HTTP/1.1" 200 
1682 

192.168.0.210 - - [26/Jun/2013:15:02:37 -0400] "POST /xxxxx/SopsSubscriptionPortingImpl?wsdl HTTP/1.1" 20 
0 258 

• Our client is saying the second call of POST which is actually making the webservice method call should not have "?wsdl" at the end of the URL.
• Could you please comment if that is correct or what should happen from a standard point of view? Is that the standard (W3C) to do the POST without the "?wsdl" at the end?