ac3 recode 23976 >> 24999

[SteMa]

I have a PAL audio track in my language, and managed to sync it to the ntsc video by converting the video to 24.999fps. I would like to keep the foreign language track too, but if I try to convert the ac3 track from 23.976fps to 24.999fps with besweet, the sound gets dirty, it's noise all along, and only sometimes I can hear some speech (probably the center channel doesn't get as messed up). Any recommendation how I could convert it? It's a stereo track and tried different bitrates (384 and 640 to be exact), but none of them were usable. Any toughts?

edit: using 5.1 didn't help either

[Susana]

Use belight (new gui for besweet) + aften (new ac3 encoder)

or

soundout (avisynth plugin)

...