Hi Eeriki,
You are correct, the system has not been designed (yet) for channel-bundling!!
At present 64k is supported, no more.
Before the release of the present system, a few people put a lot of time into making isdn part of the system.
The basic system is working as you noticed, but there simply has not been the demand for channelbundling. (I have not seen it on the lists anyway) If you want a chance to learn linux/sme/isdn, than here is your opportunity!
If you do a search in all the forums for isdn, you will find enough info to get started.
If you need a solution with channelbundling NOW, look at
www.fli4l.de.
When I need a 128k solution, I'll use a fli4l box, 10 minutes work, and give another old computer a good home!
hint: if you type isdnctrl at the prompt, you'll see lots of possibilities!
good luck
kees