T-mobile's simultaneous Voice & Data on Verizon iPhone?

Hi :) Here are some facts and one very irritating query stuck in my head :|

• We all know Verizon's iPhone 5's do not support simultaneous Voice & Data on Verizon's CDMA network.
  
• Whereas, AT&T's iPhone 5's do support it on AT&T's GSM network.
  
• Also, Verizon's full-price iPhone 5 is being sold carrier-unlocked.
  
• Above all, Verizon iPhones also work on GSM networks, so I can use it with T-Mobile!

The only question is, does the Verizon iPhone 5 work having simultaneous talk & data while operating on 3G GSM networks? Like on T-Mobile or AT&T?

It would be really great if someone could actually try it out and confirm :D

Gaurang