I looked a bit more into it, how to control those pins.
The wiki mentioned an easy way to configure them as gpios.
I guess they are talking about switching the mode to 4 in the
Core Control Module Pad Configuration Register Fields.
But as far i read and see they are locked by firewall and set in the signed and encrypted(?) part of the x-loader:
"X-Loader: 1) Sets up the pin muxing." (see http://wiki.maemo.org/Firmware_hacking).
So maybe it is easy, but i cant see it yet..
systestmode seems to give you out pins only (havent looked in it more deeply yet)