Created attachment 24760 [details]
Patch that adds support of flow key extraction.

Spring Webflow may use POST parameter as session identifier. It is very tedious task to add proper expression extractor to every HTTP request element. I was not able to configure JMeter proxy properly to add parameter extraction automatically.

To do the task I have updated JMeter code instead (I have attached patch I used). This seems extremely dirty way to do this, but at least it works for me. I think it could be feasible to do something like that in more general way, so some element could be repeated by proxy whenever some text appears in the response. I did not have a time to implement such feature myself, but I though someone could be interested to do it.