asterisk users - Aug 2005 - Asking telephone no from caller

Hi,

I am using * behind a PBX for internal use (not yet ready to replace it
fully). Unfortunately PBx does not support Caller-ID, (or people here do
not know how to configure it) When a call comes, I want to get a
telephone no from customer, record a message and sent it as a mail, so
that we can call them back. But so far I have not found how  to do it.
Any one to hit me with a clue stick! 

with warm regards,

raj