Hey All,
I found the answer to this problem: Automatic Duck. It's a plug-in that you load into the FCP plug-ins, then import the OMF into FCP using the plug-in and then roundtrip the FCP sequence to Soundtrack Pro.
I believe it also works the other way, i.e. FCP files to Avid etc.
Here is the link for all of you out there with the same problem:
http://www.automaticduck.com