Super Joy Box 13, missing 6th axis

I just received my Joy Box 13 GameCube controller to USB converter which
presents itself as a HID game controller in WinXP.

The problem is that in the test dialog in control panel everything works fine,
but when using SDL axis number 6 is missing. This being the R-button, a combo
analog/digital button. It works as a digital button, but is not found as an axis.
Funny thing though, the L-button (identical to R) works just fine, as an axis
and a button.

I’ve made these tests on 2 different WinXP systems with 2 different controllers
using both testjoystick.c and my own code, with both the stable 1.2.9 release
and CVS snapshot. All combinations yield the same result. Everything works
except that axis 6 is not found.

I have not yet tested under Linux since I do not currently have it installed.

Any information about how to fix this bug would be appreciated.

/Jacob Kolding