A couple of choices:
1. Get the source material, not DVD format
2. Refuse the assignment
3. Import the VOB files - assuming they are 100% DVD compliant - and take the quality hit.
4. Convert to MPEG2 / PCM 48 KHz WAV and take the quality hit.
Assuming Harm's option 1 just isn't possible, I'd probably start with option 3 myself.
If that didn't work for any reason, I'd try 4, only creating a Lagarith AVI instead of an MPEG.