You can only use the 722 call trick if the DTivo is a non-RID model. Otherwise, you'll have to contact DirecTV and get it activated. This will automatically put you into a 2-year commitment extension with DTV. It doesn't matter whether you hack it now or hack it later, although it's usually a good idea to make sure it works with DTV before you hack it.
Please don't PM me or any other members looking for personal assistance. You'll do better by posting (after you've exhausted the search feature, of course) and taking advantage of the collective expertise of the membership instead of a single individual that may or may not be able to help you. Thank you and enjoy your stay at DDB!