Configure postfix to forward to isp smtp server?

[Chris T.]

I am trying to create a home mail gateway.  First thing is getting it to 
relay messages to my ISP as if I had connected directly to the isp in 
the first place.  That is without adding any information to headers to 
reveal that it went through my smtp server.  I also want to create a 
repositry of sent email for logging purposes.  I'm trying to look up the 
documentation and searching for messages that would answer what I want 
to do but it's a chicken and egg senerio in that I don't know the 
correct terms for the answers to search to find the answers.  Any help 
is appreciated.

Chris