Exchange Server 2000 and SMTP mail

Our site uses a unix-based smtp email system for all “email,” but we have an Exchange Server that we use for other collaboration (calendars, meeting requests, tasks, etc.). Right now it is a corporate policy that for regular smtp email we are to use one email client and for Exchange items we are to use Outlook.

The above scenario works Ok, except when a user sets up Outlook to do SMTP email and uses it as his/her only email client, mail can only be received by other users in Outlook. The other email client does not receive the mail.

I recently became the Exchange administrator, and I would like to work to correct this problem. Has anyone else encountered a similar situation? Any suggesstions?

Thanks!