[cvsnt] Change commit message

[Ene Stelian-Bogdan-B11248]

Hello,
 
I need to perform a relatively simple task:
Whenever a user commits with a certain "message", the commit message
should be changed to:
"[Real name] message"
 
The user's real name can be found in the passwd file or by executing the
finger command. 
However, I don't know how to hook the commit action and actually modify
the message - I can only get a read-only access to the field.
 
Any ideas ?
Thank you