SP4 Pen on SP3. Anyone try it out?

[Wilx]

I have he New pen too, but am wondering if I should be using the Pen drivers from the latest SP3 Pro downloads off Microsoft or the SP4 Pro drivers? surely it should be using the drivers from the SP4 site? also can we re-assign the buttons like on the SP4? I have seen a post suggesting to swap some drivers to achieve this, but then they say auto update tries to replace the driver and screws things up. If Microsoft are saying they are backward comparable, surely they should be giving SP3 and SP3Pro users the ability to swap the buttons with a driver update too?