First off we don't want to do that to RIM.
DM does that as part of their security infastructure. Anytime you plug in your BB, DM checks the device with your carrier and RIM servers to make sure it is what it is supposed to be. This, I'm almost sure is done to prevent someone from hacking into the phone or network.
I personally like that security and believe that most of the "WE" like it as well.
Short answer, you will have to find a good friend with an internet connection who will allow you to install DM on their comp so you can can sync your phone.
I just want a honest weeks pay, for a honest days work - Steve Martin.