Problem when submitting a deleted file

System

I am using a workflow that after an author submits a file (usually a pdf), kicks off a cgi task to set metadata, goes through an approval process and after approval executes an external task that:

1. executes iwodstart do deploy the file to production web server
2. executes iwdd.ipl to deploy metadata to production database.

This works okay but I want to use a similar scenario after a file is deleted from the workarea. But the cgi task that sets metadata is a problem; it tries to set metadata on the deleted file and fails! Is there a way to differentiate between a normal file submission and a deleted file submission? If it were a DCR, I would do it with tt_data and tt_deletedcr workflow template type constraints I guess...

Note: It is also important that the same file submission / deletion scenario can be implemented using TeamSite FrontOffice.