Problem solved, just thought I would post my solution here so no one would spend any more time thinking about it and for archives sake.
1) Import files in iMatch.
2) Import keywords from IPTC to Keywords property.
3) Export database properties with content to XML file.
4) Open XML file in text editor.
5) Find/Replace all semicolons with commas.
6) Import XML file back into iMatch with contents.
7) Run All Purpose IPTC Script using a comma as a seperator for keywords.
Move to iView and get on with life.
Thanks for everyone's thoughts. This probably wasn't the most simple way but it worked.