Outlook 2003 default email account

[Wes]

I am using SBS 2003/Exchange Server 2003 and Outlook
2003. I want Outlook clients to have an account other
than Exchange as their default account for sending
Internet email. (I am doing this because I want clients
to send their own email to a smtp server and not go
through Exchange).

I can change default account, but every time they
restart/log on to network the default is automatically
switched back to Exchange account. Any idea how to stop
this?

Thanks, Wes