Although I don't have a blackberry I do use Verizon here in the states. Every time I have gone to Aruba, before I left I had to dial *221 (not exactly sure of the #) or something of that nature. And when I got off the plane everything worked fine. Not sure if you still have to do that but I have included a link to Verizon Aruba info and you can click on the compatible devices and yours is listed.
Hope this helps.