An Outlook Question

I have a question for any of you Outlook 2003 experts out there:

I have 2 accounts in Outlook that I send & receive mail with: my account & my account. For each, the account, the listed email address & reply-to address corrsponds to the domain its being sent through. However, whenever I send mail, it always appears to be coming from Which I don’t want. I want all my personal correspondance to be coming from and all my business correspondance to be coming from I’ve done tests by sending mail to myself from both accounts, and when I receive the message, it invariably says from I’m assuming that everyone else has this when they get mail from me too?

Have I done something wrong? Or do I have to set something special to actually get it to pay attention to the domain I use to send mail with? Or is my install buggy? Or is Outlook buggy? etc. Any answers, links, etc, much appreciated.