Thanks. Can you explain exactly how the pressure sensitivity is supposed to work? I only know of one other tablet with n-trig that meets the requirements of PS Touch and that's the Lenovo Thinkpad Tablet.
As soon as you enable the pressure sensitivity at the Stylus Pressure options (see enclosed screenshot) you are able to control Opacity (or size) without changing at the bush settings. If you have an eraser on you Stylus you should be able to erase without going to the Eraser tool.