File updates/rev changes with stand-alone c# application from external source.

We're moving from CMS to Enterprise PDM and have many drawings, assemblies and parts we wish to keep revision history on.

I've written an application to batch AddFileFromPath, CommitAdd, ItemGeneration & UnlockFiles.

All is good up until I need to start adding the updated files which have the same filename as files already added and checked into the vault.

I've tried several different methods from clearing the cache and adding the files again, to using GetFile, GetFileCopy & LockFile and everything to this point fails.

What are the steps that I should be taking to update files in the vault with files that reside externally to the vault?

SolidworksSolidworks Pdm enterprise Pdm