I've finally solved the problem. There just remains the problem of loading the driver on boot.
Anyhow. In case you are still looking for a solution, here is mine:
Actually after you've loaded the driver to the kernel and connected to your network with ./RaConfig2500 you have no more driver problems. But on my system the computer wasn't assigned the right IP-Adress so:
/sbin/ifconfig ra0 YOUR_IP
The next problem was the default gateway. This was the Adress of the router, so:
/sbin/route add default gw IP_Router
After you've done this your Internet should be working. But you cannot surf, because Mozilla (or whatever you are using) doesn't now where to go to when you type an adress. This brings us to the DNS (Domain Name Service). I'm not sure if my solution will work on your computer. I gave the adress of the router as a name server. This might be router dependent. Anyhow you have to edit a file /etc/resolv.config. And an example from one of the books I borrowed looks like this:
These are only the first two lines of five which are enough.
To automate the tasks I've written a script. This makes me have to login as root to execute it, but hell I can live with that. Though it causes a problem if someone wants to use the computer, who doesn"t know the root password.
And I am dissapointed of the members who have not only failed to assist us, but have totally ignored us.