Well I limited mine to 1x not because it wouldn't connect on EVDO - actually it did - but because I had heard people were pushing their luck connecting that way. In other words, Verizon was watching.
I think the key for you is the same it was for me; unblocking DUN capability on the phone itself. Now I don't know much about the Razrs - I'm still using my old LG - but in my case all I had to do was use the "administrator" password for my model (found on HowardForums) to access the root menu on the phone and undo what Verizon had done, i.e. unlock dialup networking.
I did a quick Google search and it looks like it may be a bit more convoluted for you. Check this link out and see if it helps (HowardForums again):
It seems like you'll need something called QPST, a Qualcomm utility for accessing the hidden configuration menus. There's an indication someone has it up on RapidShare, and I also found a "Hack the Razr" site ("it's your phone ... make it so"), which looks like it has the utility for download. The link for that:
I'm still connecting tethered, so it's still possible ... The only recurring problem I have is that when I'm connected to my own wireless router at home, every time a page is a little slow in loading the laptop throws up the DUN connection window and I have to cancel it out. Minor price to pay I think when I can have Google Maps up & running in the passenger seat while I'm heading cross country in the Triumph!
Hope it helps. Good luck!