it will be the exact same procedure but with some modifications to make it work with cable. .....
Unfortunately I dont think it is the same procedure as for the boxes which can be done your probably going to have to get your hands dirty and do some jtagging etc. For cards that are paired to boxes that cant be jtagged or otherwise accessed (2110's, PVR type etc) then your unlikely to ever to be able to extract the required info to pair those cards.
As i've said before, unless you have one of the older generation boxes then your effectively stuffed when it comes to trying to share your card. You just can't get into the boxes to get the required info !
Remember, theres a lot of boxes you cant even get the boxkey from, getting the pairing keyset will be a similar obstacle.