Hi Dejan,

we support AS3 through the Flex client
http://www.lightstreamer.com/distros...nce/index.html

on the other hand, the Flash client, that's the one that gets its data from the JavaScript client, is still an AS2 component
http://www.lightstreamer.com/distros...nce/index.html

So you can either use the flex client, or, instead of using our Flash client, use the FABridge.
Its original documentation is here: http://help.adobe.com/en_US/flex/usi...1f3a-7ffd.html
I've not checked but I think that even after the migration to apache the FABridge is still available directly in the sdk. Here is its bugtracking: https://issues.apache.org/jira/brows...-summary-panel

Would that work for you?