Adding methods to a WebService consumed by BizTalk

Our team added a couple of methods to a web service that an orchestration need to call, but we were getting an error when BT tried to call (via WSE) the new method:

Value cannot be null. Parameter name: methodname

It turned out that the Send Port was not being refreshed in the BizTalk administrator, so the easiest solution was to create a new send port for the same web service, point all the orchestrations to the new send port, delete the old port, and rename the new port to the old port name.  After restarting the process, the error was gone!