[rules-users] Drools Flow, constraint parametrization

Hi, I'm not a new drools user but I started to test rule flows (5.0M5) recently and I'm stucked, so any clue will be welcomed :). I'm testing how to share a StatefulKnowledgeSession between N rule flow instances. I'm trying to parametrize each instance with process variables at start time but I don't know how to use them from rule constraints (in event waits, splits, etc.). I've read the documentation and I've found this text related to constraints "Both rule and code constraints have access to globals that are defined for the process and can reuse imports at the process level." I tried it assigning (from an action) a variable value to a global variable but it's not working for me. ¿I'm missing something? Thanks in advance! Ricardo.