[otrs] Help with email

I've asked before, but haven't really gotten any help and I'm desperate at this point. Could someone please help me figure out how to add a Reply-To: header to all outgoing mail from otrs? Basically, I want to take the original From: address and put it in the Reply-To: address and then put a different address (that I pull out of my head) into the From: header. Basically, right now messages from otrs come from: otrs@blah.com I want it to come from: helpdesk@blah.com with a reply-to header of: otrs@blah.com Could someone PLEASE help me? Thanks in advance.