Well... I tried something different with the synch.bin files, and found the synchronization goes rather well with around ten different settings (with a slight difference in terms of speed).
So forgot the 3/5 step.
But just after that the first troubles: It tries to load /dev/pts/2 and it fails (I checked it and found that in dev/pts there are only "0" and "1").
And then it fails the 4/5 step, so the connection to provider.
I tried to recompile the kernel but in /usr/src there wasn't the sym link to the kernel...where can I found it?
And what should I load/change in my kernel configuration with the hdlc support?