First part of a fix related to bug SDK-17104 (this broke when we moved to direct AST generation). I missed this feature in my initial advanced CSS check-in too. This change only addresses the velocity side of the fix. Direct AST gen is the other part which will have to be in a separate changelist.
QA: Not yet (although with -keep true you could test this works)
Partial fix part for Advanced CSS work, related to
SDK-17104 - Assigning an effect trigger in CSS no longer works in Flex 4