Is Samsung looking into enabling separate switch for data roaming on different Sim. Most other Android phones already support such features. The are few times I got charged for accident switching the Sim during overseas trip.
Until Samsung implement separate Data Roaming switch for individual SIM, u can consider the following work around (Note: I personally have not tried using 2 SIMs on one phone while travelling overseas):
1) Ensure Preferred SIMs Mobile Data (under SIM manager) is set to the phone# that u want to use Data Roaming.
2) Ensure Data switching is disabled
3) U can disable the SIM that u are not using (no call, sms, etc)
