time out in webservice (c# calling websphere server) when calling second time???

Question

Hello, I have implemented a webservice by using websphere. an c# client calls this service successfull, however it always gives a timeout in the second call. The first, third, fourth call etc.. are alway successfull but the second fails all the time (timeout). Monitoring the servlet on the websphere side shows that there is no incoming traffic from the second c# call. I tried both ways (synchrone-call and the asynchronious variant) but the second call always causes a time-out. the .jsp testpage (generated by the websphere environment) works fine all the time, so the suspecion points to c# who has an idea what can cause the trouble. thanks in advance leon van rooijen