Off-site exchange server

I am trying to retrieve my work e-mail from home. I have set the e-mail account to (cach exchange mode) If I send a test message to my work account from a free e-mail account, the server allows me to see that message at home, but still will not allow me to view messages already in my inbox at work.. At work I can see the sent test messages, but once i send/recieve at work I can no longer view that message at home.. I am using outlook 2003 at work and trying to retrieve mail at home with microsoft exchange server..
A little nudge in the right direction would be greatly appreciated..!!