How to use a thread and timer in webservice method?

In a webservice I called a remoting method. The webservice is consumed in a client application. In the Client application 2 minutes timeout is set. But even after the timeout exception is received by the client the webservice method (which in turns called a remoting method) is still executing. I need to avoid that. Hence after the 2 minutes time I'd like to stop the webservice method execution.