Remuxed H264 MKVs have double-fast video and no sound

[Cabal]

Not sure if this is a Mac thing, a Snow Leopard thing, or a general PMS thing. Here's the facts:

- PMS 1.52.1 on an older Mac Mini, OS X 10.6.8 (no transcoding, tsMuxer only)
- PS3 with the latest firmware
- Fresh DVD rips of various movies with Handbrake 0.9.6, either as MP4 High Profile preset with two audio tracks (the default), or as MKV High Profile with two audio tracks (the default)
- All files play perfectly in VLC 2.0.1 (for testing purposes).

Results:
- MP4 played natively on the PS3: OK (can even switch audio tracks from within the UI)
- MP4 played via tsMuxer on the PS3: OK with either audio track chosen
- MKV played via tsMuxer on the PS3: Double-fast video, no sound, regardless of which audio track is chosen

Any ideas? If this is a tsMuxer issue, is there a way to set up Mencoder to remux only without transcoding? If so, I'm having trouble finding it.