Hi tinypoodle!
It works - thanks for your great hint.
I did not know loadfont at all. But as I red - loadfont is some stripped down setfont.
All I had to do is to decompress my psf.gz-font-file (with gzip -d *.gz) and load it with "loadfont < font-file.psf".
Thanks again for helping me - and my weak eyes.
deetee