FX5200 - Blank screen on TV

I'm using a noname card with the Gf FX5200. For TV it only has a S-Video
connector, so I use an adapter from S-Video to Scart.

In the past, setting the TV Output Format to SVIDEO resulted in blank
and white output, but setting it to COMPOSITE solved the problem.

Since I upgraded my Linux driver from 6111 to 6629, setting TVout to
COMPOSTIE results in a blank screen (SVDIEO is still black and white).
WinXP with the newest driver shows the same behaviour, but with older
versions it worked with the COMPOSITE setting like in <= 6111 with Linux.

Does anybody have a solution for this (except downgrading, this is not
an option because linux >= 2.6.9 requires nvidia >= 6229)?

Thomas