They indeed disappear. As Erick Ellis from Microsoft explains:

We removed the Flash API because it was too simplistic and failed to address the core scenario which is Messenger’s use of flash. You could stop and start it, but you couldn’t control duration, end state and several other aspects. We just had to pull the plug on this vs. making an investment we weren’t sure would meet the quality bar for Whidbey.

Also there is more information available on the  MSDN Product Feedback Center:http://lab.msdn.microsoft.com/productfeedback/viewfeedback.aspx?feedbackid=68a88354-d4f0-493e-bee8-bf3310e914de.