@Frank Silveira 

you will have to write custom mid server script include for this

Invoke this from the Post Export Script to rename the file post export is done.

But this involves writing java package + javascript. So I would suggest to inform business team that even though this is possible it might lead to issue going forward in terms of maintenance.

Consider on some day the file got placed but there was some error in renaming so it might lead to issue.

Regards
Ankur