Plugin – work approval

Hello,

I am looking for plugin which allow my registered users to add work in *.doc for example, and after that we work on this file and change status of his work like “work in progress” “waiting for approval” “finnished”, and what is important user will get notifications on mail about every status change.

I have tryed Document Revisions plugin which works great about those status changing etc but its missing notification system :/

Thanks for help.