You may want to post in the other studios, but if you bring it back into AE and you have an alpha channel, the issue is that Vegas and Corel are interpreting the footage correctly. You many need to change the way you are importing into the programs to tell the software that there is an alpha channel and it needs to use it, that's how it is in Avid.
Johnny Cuevas, Editor
"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.