How can I use a "default branch" inside a pick activity using workflow foundation 4?

I'm using a pick brabch acitivity with开发者_运维百科 two branches. Each branch has a receive action, but when the workflow is paused on the pick activity waiting for a cliente comunication and I call a service method wich is not in those brach activity I got a error. Actually I think the workflow enter in an infinite loop or something like.

Is there any way to buil a "default" branch, like a defaul case in a switch/case contructions?

You can add a PickBranch with a Delay activity as a timeout branch if none of the other branches is called within the alloted time.