ofmipd to rewrite return-path header

[FastWeb]

What is the syntax for the name.cdb file to re-write a
from or return-path header?

For example I want to re-write the From header as follows:
Incoming From           Rewritten From
*@*.domain1.com         [EMAIL PROTECTED]

Where "*" matches anything.

Also: is it possible to rewrite the Return-Path header
and not touch the From header?

Thanks,
Ken Jones
Inter7