*If* you can do it in your E-mail program, how to do it depends
on what E-mail program you're using. Which is it?

Haven't done this but look at:

Tools  Create Rule from Message

Then check:
All Messages
Reply with Message
click on underlined message. Looks like you have to create a .eml file with
your reply in it.

Good luck
Billh

To create a rule for e-mail messages to automatically with a return TEXT
message.  Test by sending an email to: LsuEdu@Bellsouth.net

 1.. On the Tools menu, point to Message Rules, and then click Mail.
 Message rules cannot be created for IMAP or HTTP e-mail accounts.

 2.. If this is the first rule you are creating, proceed to step 3.
Otherwise, on the Mail Rules tab, click New and proceed to step 4.
 3.. Select the conditions for your rule by selecting the desired check
boxes in the Conditions section. (You must select at least one condition.)
 You can specify multiple conditions for a single rule by selecting more
than one check box. Click the and hyperlink in the Rule Description section
to specify whether all of the rule conditions must be met before the
specified action occurs (and), or whether at least one must be met (or).

 4.. Specify the actions for your rule by selecting the desired check boxes
in the Actions section. (You must select at least one condition.)
 5.. Click the underlined hyperlinks in the Rule Description section to
specify the conditions or actions for your rule.
 You can click contains people or contains specific words in the Rule
Description section to specify the people or words you'd like Outlook
Express to look for in messages. If you enter multiple people or multiple
words per condition, use the Options button in the Select People or Type
Specific Words dialog boxes to further customize the condition.

 6.. In the Name of the rule text box, select the default name or type a
new name for your rule, and then click OK.
Notes

 a.. You can create a new rule by selecting an existing one on the Message
Rules tab and clicking Copy. This is helpful when the new rule you want to
create is similar to an existing one.
 b.. You can create a rule from a message by selecting an e-mail message in
the main window and then on the Message menu clicking Create Rule from
Message. This helps by automatically filling in the name of the person on
the From line; no other information from the message, however, is entered
into the rule.
The fact that in Mohammedan law every woman must belong to some man as his
absolute property - either as a child, a wife, or a concubine - must delay
the final extinction of slavery until the faith of Islam has ceased to be a
great power among men.

Winston Churchill - London, England
http://www.winstonchurchill.org