Crap! I thought your Collada export was working really well too! I've been exporting models, checking for inconsistencies and such and you've really done an incredible job. Not to mention the Collada .xml output is fantastic for post-processing and conformity checking... So...
How about .fbx? AutoDesk has a freely available SDK that I "think" might solve your multiple UV issue and others. It incorporates support for Collada 1.4, .obj and .3ds formats as well...
At the bottom of the page:
http://usa.autodesk.com/adsk/servlet...112&id=8224926
They have very good SDK docs as well.
A couple of years ago I downloaded the SDK for a project that I was involved with and it looks good. Unfortunately, the project got scrapped (as they often do it seems) and I dropped my programming part of it.