SM5100B-D and IPv6

Hi all
The SM5100B-D seems the most popular GSM/GPRS module for Arduino
Does this come with an IPv6 stack ?
If not, is there any GSM/GPRS module that does come with an IPv6 stack ?

Also can anyone confirm that the GSM/GPRS module does work with either the AT&T or Verizon USA networks ?

Thanks in advance