After a few hours of checking every detail of the PAL timing, I got a working PAL example.
I should believe it when Chip says:
PAL is a real pain! ...
What seems to be very important is the transition from V-Sync to the first (blank) line. After this was right, I finally got colors. Just not the right ones. The PAL coefficients in the Prop2_Docs seem to be wrong, and I don't know how to calculate them.
So I just tried around, made a mix from NTSC and PAL coefficients and got accetable but not perfect color hues.
Attached is the code for the ones that live in the PAL world.