Pankaj , would like to comment as to where you read the stuff you are mentioning..
Cause only recently they have created a Hand-set capable of working as dual CDMA as well as GSM , and i doubt to the concept of R-UIM and NIC.
If the handset’s are capable of working as a dual one..
then only the changes in the Signalling messages in accordance to the format used between CDMA and GSM , the roaming could be possible..
Awaiting your comment in this topic