Is it possible to use the Verizon sim for data and a 3rd party sim for voice?

[J2thaD]

I have a Verizon Black Berry Storm 9530. I will be traveling to Europe soon. I was looking at 3rd party sim cards for voice as they offer cheaper calling rates than verizon does internationally. I was interested in Verizon's global data plan though. I asked a verizon customer service rep if it would be possible to use the Verizon sim card for the global data plan, and swap it for a 3rd party prepaid sim for voice when I wanted to make calls. The Verizon customer service rep told me that would not be possible, because when I swapped cards, then tried to put the Verizon sim card back in the black berry, that, it would need to be activated again, and it could only be activated from the U.S. Has anybody tried to do that before? Is this true? Verizon customer service reps have lied to me before when I made inquiries, seemingly to try to ensure that they get my business for all of their expensive services. Any input or suggestions would be much appreciated.