I have tried your patch Gregoire and it doesn't work here (HVR4000 Lite). When tuning to a DVB-S or DVB-S2 I get a black screen. When using the original patch everything works fine (on previous vdr-1.5.12 patches)
If you use the patch from http://www.linuxtv.org/pipermail/linux-dvb/2008-January/022762.html it should work, the previous one didn't declare the card as DVB-S2 capable.