OK, I posted all my remarks to the above email address.
But I got 1 step further also.
When I use Sonic Foundry SoftEncode to transcode the AC3 and use this file to author a DVD it plays fine on all devices (also the DV-525).
So now I use AC3Machine to transcode the AC3 to a new framerate.
Afterwards I transcode that AC3 with SoftEncode to have a correct playable file.
CYA,
II00I00I