Correct. You just program the xv according to the link posted in the last post, call cricket and add the XV to your account. You'll need the ESN to do it. You can find it under the battery of the XV, or in the EPST screen (##778)
When cricket activates the phone, tell them it's a motorola razr. Otherwise, they're likely to tell you that you can't have any extended services, and won't add/change anything on your account for you, unless you scream and rant and rave until they give in.
I'd also recommend making any changes you want BEFORE switching the ESN nurabers. If you want travel time, WAP, MMS (assuming you don't already have them).. make those changes, THEN switch the ESN.. that way you don't even have to argue with them.