To get the white button to pop out your favorite scripts just add these settings to your keymap.xml. If you don't want the left and right trigger to change blade take out the <lefttrigger> and <righttrigger> parts in the following. But make sure you add your DialogSubMenu.xml to the pal folder in the skin, I used mine from previous builds.
Hope this helps, but might not
<gamepad>
<white>XBMC.ActivateWindow(SubMenu)</white>
<black>XBMC.Skin.ToggleSetting(HomeViewToggle)</black>
<lefttrigger>left</lefttrigger>
<righttrigger>right</righttrigger>
</gamepad>
<window1112>
<gamepad>
<white>XBMC.ActivateWindow(SubMenu)</white>
<lefttrigger>left</lefttrigger>
<righttrigger>right</righttrigger>
</gamepad>
</window1112>
<window1114>
<gamepad>
<white>XBMC.ActivateWindow(SubMenu)</white>
<lefttrigger>left</lefttrigger>
<righttrigger>right</righttrigger>
</gamepad>
</window1114>
<window0>
<gamepad>
<white>XBMC.ActivateWindow(SubMenu)</white>
</gamepad>
</window0>
<Settings>
<gamepad>
<white>XBMC.ActivateWindow(SubMenu)</white>
<lefttrigger>left</lefttrigger>
<righttrigger>right</righttrigger>
</gamepad>
</Settings>