Can you use framework-less Flex 3 SWCs within CS3? I assumed that you could do this if the compatibility-version flag was used and you didn't use any of the Flex framework. I haven't been able to get this to work, however. I asked about this about a month ago and the all-knowing Matt Chotin said it should work, so I'm hoping there's something I'm missing.
A colleague of mine, Crystal West, created this example to show the issue: http://deitte.com/swc_test.zip The example has two SWCs within it, one created using Flash Authoring and one created using Flex 3. Try compiling swc_test.fla with just flash_bc_ads.swc in the same directory (that is, remove flex_bc_ads.swc). The fla should compile fine. Then try with just flex_bc_ads.swc. You should get compile errors related to AdTranslator class, etc. She tried a lot of variations on compiling with flex_bc_ads.swc, and nothing worked. flex_bc_ads.swc was built using the compatibility flag and doesn't use any of the Flex framework. She also tried compiling the Flex SWC using compute-digest=false (as recommended by Tim Walling http://timwalling.com/2007/10/22/compiling-flash-cs3-compatible-swcs-with-flex). That didn't work either, and, according to some of the comments on this blog post, didn't work for others. Any suggestions?
