This will also be the "initial" or "first" checkin of the file to the vault....
In PDM you can set the file types that are added automatically to the vault. On group settings ->Adding files create you can create a list of files types that are added automatically to the vault.
For checkin you ca use dipatch. In dispatch on add automatically can check in the files.
I totally forgot about the auto check in for curtain file types. No the route i was going in but works out better. Also raises the question on why PDF was not set to "auto checkin"....