Try using this method:
1) In Tools | Options | Mail Format | Internet Format, under Outlook Rich Text Options, from the drop-down list, select "Send using Outlook rich text format"
2) Create a new email message in rich-text format.
3) Insert the contact as an attachment.
4) Add the recipient.
5) Double-click the recipient address and make sure it's set for "Send in Outlook rich-text format."
6) Send the message.
If that doesn't work, talk to your Exchange administrator about unblocking RTF content to the Internet.
--
Sue Mosher, Outlook MVP
Author of Configuring Microsoft Outlook 2003
and Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers