Have a look at Gregoire's initial discussion with Reinhard here: http://permalink.gmane.org/gmane.linux.vdr/34901
Maybe the mentioned debug code helps to get this sorted. I don't have a HVR4000 here, with a TT3200 it's working out of the box...
Thanks for the info, I fixed Holger's original HVR4000 patch to work with VDR-1.5.13 and Reinhard's recent patches. The patch is attached, apply the patch after applying Holger's to the multiproto tree.