I like combining gs.TweenLite and fl.transitions.easing.* to do most of my animations. Here is how you can include the Flash AS3 library SWC in the Actionscript project library path. Step-by-step instructions are as following and also illustrated in the screenshot.
[+] In Flex Builder (3), select the Actionscript project you need to use the Flash AS3 library SWC in and edit its properties by right-click the name of the project.
[+] Select Actionscript Build Path and then the Library path tab.
[+] Click on the button that says Add SWC.
Refer to the screenshot. (I am on a MAC. the path to your SWC might be a little different.)
Enjoy.
