Спасибо вам, Snuk. The settings for the box are 4:3 / 720p so that should be alright as far goes... I'll see how it is on another TV and get back. But there are no other option to zoom in/out on the control? I'm still learning this :-)
PS. In the instructions there's a picture with something called Eingangswahl (one time options I assume!). It's got options for AV1, AV2/S, AV3/S, Component, PC, HDMI, etc. Maybe I could change something here? The problem is that I don't know how to access that.
PPS. I use composit connection right now.