C902/Z780i Volume Buttom

Sirs, help me please

I have 2 SE mobiles: C902 and Z780i
And I'm having the same problem in both: The volume button, when pressed, shows the phone status. I want to know, if is possible, change this function to change the volume.

I want to know how I change the shortcuts up the call and call-off too

Thanks

At this moment you can't set anything.