TMS doesn't populate the body of the invites for room calendars, you'll need to use the same process recommended when you want to provide the meeting details to any users invited:
If your booking includes more than one telepresence room, you will receive confirmation from Cisco TMS that the meeting has been set up, and information on how participants will connect.
Forward this information to the invitees, or paste it into the original meeting invitation and send an update to distribute the information.