Further testing.

Ozon, your initial idea (using the ipod) seems to work better. I tried with my computer screen and photoshop, using a white document that i gradually darkened than letting it cover the whole of the lens, i could dial in exactly the brightness. Firstly this is much more accurate than using the lite panel as the dimmer is not very accurate and hard to repeatedly get the same value, secondly it also seems that you need to be quite in the "middle" of the stop, if not the camera snaps to the next stop above or below choosing a random ISO. So your idea of creating different shades of gray representing different shutter speeds seems like the way to go.

I found turning the camera off and on again will stop the flicker, i think it may have to do with at what point it syncs up with the 50 Hz flicker, so if you happen to have turned the camera on at an unfavorable moment the flicker is more pronounced. I may be wrong, but at least it seamed to solve the problem.

double post

Ive never tried Av mode. Is there an advantage? Or samething as in M mode?

I also was able to get 1/60 and various ISO settings but wasnt able to lock it down.

exposure simulation will not give you the right shooting information for movies. no matter what mode you are in, the camera shoots the movies the same way, but only movie mode actually tells you close to what it will do when you press record. At least that's my understanding.

Are you really sure that you are not dealing with the photo mode during the video recording?