hey there m stan,
if you're just wanting to move/save the audio files as data, you can use Toast(Mac, PC or ISO) or Disk Utility(Mac).
the spec for DVD audio when converted to M-PEG 2 standard for DVD video is nowhere near 24- bit/96K or 24-bit 128K. these are the standards for pro audio recording & these files are then down-rez'd for audio CDs @ 16-bit/44.1 K. the current audio standard for digital video is 16-bit/48K, so even if you could get the audio & DVD on the same disc, one or the other would be compromised as there isn't enough space to accommodate all of the data. generally the audio is sacrificed 1st, when using a "Pro" DVD authoring suite such as Scenarist or DVD SP. there really haven't been many DVD-Audio(mostly in 5.1) discs produced for a few years, if you have any, one thing to try might be to contact the firm that pressed them.
good luck.