[DSP8000]

It seems that when the program (Vegas) renders the Mpeg file with the audio file, it messes the dts audio file.

Of course, Vegas is not capable of encoding to DTS or multiplexing the streams.Same aplies for DVD Architect.

Here's a workflow that will get you what you want:

1. Render your timeline to MPEG2 from Vegas
2. Make DTSWave file with SurCode (2.0 or 5.1)
3. Get a copy of DVDLab (trial version available)
4. In DVDLab import the assets
5. DVDLab will multiplex the streams for you
6. Author the DVD

NOTE: I've never done a DVD with DTSwave but I'm assuming that DVDLab will do the job for you.
DVDLab supports DVD authoring with DTS streams.

Hope this helps.

DSP8000