Tvout for Ati radeon M9 on linux giving black&white blur on tv-screen

Hi,

I have a laptop with a Ati Radeon M9 graphic card. And want to use it
with my Svideo Tvout. The laptop is running linux 2.4.21 (mdk 9.1)

I installed the latest ATI Proprietary Linux Driver 3.2.5 for my
X-server (4.3.5).
After this I configured X using the fglrxconfig tool, included in the
driver. Set mode to "clone", enabled "tvout", set tvstandard to
"PAL-G"(i'm in netherlands), resolution-modes 1028, 800, 640.

After this my tft-screen and all is still working like it used to. My
tv is now flashing some garbled black and white lines. TV is a recent
thomson widescreen.

I suspect I did not set the correct v- or h-sync or modelines or
whatever.

Anybody got this to work?
Anybody got any hints?
Anybody got hints how to configure X for this?

Any help is welcome, Ronald