You can just set the windowSoftInputMode property in your window.
Generally speaking, you can assign to this property any combination of two types of constants: visibility states (ALWAYS_HIDDEN, ALWAYS_VISIBLE, HIDDEN, UNSPECIFIED or VISIBLE) and adjustment options (PAN, RESIZE or UNSPECIFIED).
In your case you can combine SOFT_INPUT_STATE_VISIBLE and SOFT_INPUT_ADJUST_PAN.
Just make few changes in your .tss file:
"#yourWindowID": {
...
windowSoftInputMode: Titanium.UI.Android.SOFT_INPUT_STATE_VISIBLE | Titanium.UI.Android.SOFT_INPUT_ADJUST_PAN
...
}
You can find more information here.