When upgrading to Office 2007, most add-ins working with OLE Automation fail.  My enterprise customer has 3rd party OCX files with licensing issues for upgrade or no newer version of the OCX is available.  Since this is a financial institution, they live and die by Excel automation.

Where is the best place to start when rewriting these?  Where is the authoritative source for API's, new Objects, etc. for Office 2007?
thanks in advance for answering an Infrastructure gal on a App / Office compatibility project.