postfix as relay and address rewriting

[dino muzic]

hi,
 
have basic question to ask. how can I rewrite recipient address from 
"u...@outside.com to u...@inside.com"?
my configuration consists of internal mail server (@inside.com) and postfix 
relay situated in between internal lan and isp.
I have already configured postfix for outbound address rewriting :  
u...@inside.com => internal server => postfix => u...@outside.com, 
but I can't figure out how to do it in reverse!
 
 
 
any help will be greatly appreciated
 
thanks
 
dino muzic