Mail rejected problem

I have a Postfix server whit 2 ip address, 200.43.76.xxx (for postfix) and 200.43.76.nnn (por bind), but when I send an email, this mail is rejected because the origin ip address is 200.43.76.nnn instead of 200.43.76.xxx.
How i can change my origin ip address to 200.43.76.xxx ?

Thanks in advance.

 

Take a look here: http://www.howtoforge.com/forums/showpost.php?p=42658&postcount=2