MPEG1 Audio sync problems (still...)

[piscator]

I want to convert MPEG1 videos (m1v) with MPEG layer 2 sound (mp2) to XviD with mp3. I've tried dozens of different things, but everytime the audio is out of sync with the video by about -300ms (for one particular clip, other clips are also out of sync). I've found quite some threads on this subject, but none gives a solution. The dumb thing is XMPEG works perfectly (picked the suggestion up along the things I read, but I'd like to use VDubMod (using v5.1.10.).

Note that you can't use DVD2AVI or DGindex with MPEG1, so you've to open it directly in VDub.

I tried the following.
+ Opened the mpg (with video and audio), processed it to XviD (sound is WAV then). Out of sync.
+ Got a WAV from the mpg, converted it to mp3. Process the MPEG to XviD. Then muxed the MP3 in. Out of sync.
+ Demuxed the mpg to m1v and mp2 (using TMPGEnc or mpgtx). Same problem. Out of sync.
+ Frameserved it with AviSynth, using DirectShowSource. Out of sync.
+ Frameserved it with AviSynth, using MPEGSource (from MPEGDecoder). But it only shows me the first 24000 frames (approx) of the total of 52000 frames (approx). It is in sync, but I've only got half of the clip.... :sly:
+ Frameserved it with AviSynth, using MPEGSource(file,-2). It gets me the whole clip, but the result is out of sync now. :scared:
+ Frameserved it with AviSynth, using MPEG2Source (from DGDecode), but it doesn't accept MPEG1.
+ Timestretching isn't a solution, since the video and audio are about the same length.

Any other suggestions or preferably solutions? ;)

greetz,
Piscator