It is fairly easy to import Flash components into Flex projects. The trick is to include the SWC in the Flex project library path. Step-by-step instructions are as following and also illustrated in the screenshot.
[+] In Flex (3), just select the Actionscript project you need to use the Flash SWC in and edit its properties.
[+] Select ActionScript Build Path and then the Library path tab.
[+] Click on the button that says Add SWC.
Refer to the screenshot here. (I am on a MAC, the path to your SWC might be a little different.)
Enjoy.
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