Well, i've looked in a lot of places, but i cannot get a real dos disk.
Instead i downloaded a DOS 2.5 and DOS XE 1.0 from the net in ATR image format.
The next step, as i saw, is to got a special cable, wich can connect the 1050 with the pc.
I've read on the SIO2PC webpage, that i need a cable, named "1050-2-PC", but where can i get it? I've already tried ebay.