Connecting slider functions to a tablet

[Gimp-2.4.5 / OpenSuse-10.3 / Wacom Intuos 3 tablet]

Hello all,

as it's very inconvenient to rotate a rectangular brush
to a specific angle within an image, I would like to do
this with the help of finger slide on the wacom intuos 3
tablet, ie.

   finger up -> brush turns right
   finger down -> brush turns left

How can I connect this feature (located as the rotation
angle slider in the brush editor) to my tablets touch strip?

Alternatively, is there another way to rotate brushes
without leaving the image window?

TIA,
Frank