InstallAware

I am using Web Media blocks to separate runtime and help files. I need to check our help files to determine if they are older, so I can download new one or not. The problem is the help files don't contain a version number, so I want to read the date from the file to determine if it needs updating. InstallaWare allow the version of the file to be read, but how can I get the date from the file.

Thanks

John