Read this thread for information about how to get a device that was not intended for your network (ie from Verizon) on a GSM provider and get the data features working.
http://www.blackberryforums.com/gene...-t-mobile.html
Note that this thread is for AT&T and TMobile in the US. And links are provided for the Service Books for those providers. It will give you all the steps involved.
However, you still will have the problem of not having the Service Books from your provider. And unless you can get them, you likely will not succeed in getting the data features working.
You would be better served by getting a device that was not from Sprint or Verizon because you will have the same problem. It's not that he devices are locked or unlocked. The problem is that your service provider does not support them natively.