how to do voice call through SIM2

view story

http://androidforums.com – I have dual sim. I have set SIM1 as default SIM and data connection provider. Now I want to do voice calls only through SIM2. How do I do ? right now , whenever I'm dialing calls are going through SIM1 .... I want to route my calls through SIM2. Please guide. phone OS: Android 4.0.4 OS (General)