OK, I found the document that tells you how to do this!!
And Here it is (it's Q223876):
SUMMARY
The Internet Mail Only installation option (IMO) of Outlook, unlike the Corporate or Workgroup option, does not have the Out of Office Assistant to automatically reply to messages when you are away from your computer. You can emulate this feature in IMO by creating an e-mail template and defining a rule in the Rules Wizard to auto-reply with the template.
MORE INFORMATION
Defining an Automatic Reply Template
Open a new Outlook message formatted as plain text.
Type whatever information you would like to appear in your reply message.
On the File menu, click Save As.
In the Save As dialog box, click to select the Outlook Template check box in the Save As Type list.
Type a name for your reply template in the File Name box, and click Save.
Defining a Rule to Send an Automatic Reply
On the Tools menu, click Rules Wizard.
In the Rules Wizard dialog box, click New.
Under Which type of rule do you want to create? click Check messages when they arrive, and then click Next.
Under Which condition(s) do you want to check?, click to select the Sent Only To Me check box, or any other criteria you want, and then click Next.
Under What do you want to do with the message?, click to select the Reply using a specific template check box.
Under Rule Description, click the underlined phrase, a specific template.
In the Select A Reply Template dialog box, click the template you saved in step 5 of the previous set of instructions, and then click Open.
Complete the Rule Wizard instructions, click Finish and then click OK.
The Rules Wizard rule to "reply using a specific template" is designed to send the reply only once to each sender, during a session. This prevents Outlook from sending repetitive replies to a sender from whom you receive multiple messages.
During a session, Outlook remembers the list of users to whom it has responded. Restarting Outlook deletes this list, resetting the rule to start again for each sender.
NOTE: Outlook must be running for the Rules Wizard to auto-reply. Also, it must be configured to periodically check for new messages and set to hang up when finished sending and receiving.
For information on changing the default message format, click the article number below to view the article in the Microsoft Knowledge Base:
Q223876 OL2000: Selecting or Changing Your Message Format
Let us know if this works...Mark