How to detect release of file handle?

AmitTrialWorks

Has anyone used the Windows API to detect when a file is close to then use the CheckinCmd to check in the document?
The problem that I'm trying to solve is that when I open a document using the OpenCmd only Word documents are automatically checked in.

devsupport suggested the following:

"use the CheckinCmd to check in the file after you have detected that the file is closed. This latter part is not supported by the SDK; you would need to rely on Windows API's (or ACROBAT API's in the case of a non-integrated ACROBAT READER app) to monitor the release of the file."