Well I have something running. Took a lot of time/effort. 
Is it known that pax doesn't seem to be available on the ramdisk
Also I had trouble ftp-ing the binary sets to the system using sysinst.
Workaround: run sysinst using ra1 as disk, default partition scheme. Then
quit sysinst; mount ra1q on /mnt2; ftp (manual) the sets to /mnt2/INSTALL; 
untar pax from base.tgz on other machine; ftp pax to /mnt2; symlink /mnt2/pax
to /bin/pax (space problem on ramdisk); umount /mnt2; rerun sysinst.
Then install on ra0, default partitions, install from 'unmounted device', all
except X things.
I am a bit astonished that no-one mentioned the pax problem on the mailing list.

Anyways, I am on my way to get the MVII running.

One more question. Booting NetBSD from the network showed 3 disks: ra0 (rd54),
ra1 (rd54) and ra2 (rd51). Sysinst only let me choose between ra0 and ra1.
(ra2 is actually an rd53, but I saw somewhere rd51 is default for unknown disks)
Can I use ra2 when the system is running from the sets?

Greetings
Alex.