Thanks for your tests!
I've tried mkvmerge. Mkv should be my new target container so this could be sufficent. The warning about 10 bytes non AC3 Data appeared here also.
Unfortunately, the new mkv File has problems while skipping in VLC and crashes ZoomPlayer without even starting to play the video
But i think the is the right direction. I will investigate that furter. I suppose the parameters for the muxing must be adjusted...
If anyone has more ideas about the skipping and crash: any help is appreciated