Bulk file rename and custom property edit

Hi Guys,
We're going through a massive evolution of our drawing system andhow it integrates with the rest of the company, and have been giventhe go-ahead for a completely new numbering system.

Because we already have so much drawn in Solidworks, we need tochange file names (which represent each part/drawing number) forthousands of files. Each file will have a pretty specific filename, so none of the numbers in the existing system will match up,and we also need to keep a record of the old drawing number, whichwill be entered into our "replacing" custom property box. At themoment it is being done manually, file by file, but surely there isanother way?

Is there a batch program anywhere that will do exactly what we needand maintain links and references, and be able to update the customproperty with the old file name? I dont know much about API but imwilling to give it a go too if it can be done, as im interested inlearning about programming for solidworks anyway...

Your help is much appreciated!
Regards,
Dana MeynardSolidworksGeneral