I was using Debian Kernel 2.6.8 which ist the highest kernel number you get when looking for "kernel-source" with apt-cache.
Now I found that I have to use "linux-source" instead.
So with "apt-get install linux-source-2.6.12" I've got a kernel that supports the DMA on my board!
So I was able to build my HDD-copy-machine. You may have a look at it on
(German text only)