Return-path in head of message?

Hi All! Knows anybody how to change (one by one for each next mail) variable in php.ini file from my script? sendmail_from = ... ;for win32 only Everytime, I use function MAIL(), there in head of message is row "Return-path: ..." but I can not change it - every mail (even if the 4th parameter in mail() function is specified with "From: ...anothermail...\nReturn-path: ...anothermail...") has in header "Return-path: ..." (with the e-mail addres specified in php.ini). Please, help me!!!!!! Thanks Ketan