"I have one movie in Architect and i want have many chances for Audio"

Just add audio tracks to the timeline. The separate audio files will be included (muxed) in the VOB files for that title -- the viewer can switch tracks with their remote, or you can add a menu to switch tracks. The default track to play is set in the project properties.

"i choose AC3 5.1, is AC3 for all, and Architect recompress the Stereo
and i not want it,"

Go to the optimize dialog (under FILE)... You can set the project defaults for video & audio separately, and by going to the different tabs in the dialog, you can often turn (re) encoding on or off. OR you could try to encode your 5.1 ac3 before importing into DVDA, and then set the project defaults to PCM. If that doesn't work for you please post your results and I'll give that & maybe another couple of methods a try.

It's so unusual to include PCM audio I've never heard or read about anybody trying. Normally DVDs use one stereo ac3 and one 5.1 ac3, perhaps throwing in a DTS track. It's usual to have audio encoded to ac3 before import into a program like DVDA, which will handle one stereo ac3 & one 5.1 ac3 track easily without re-encoding anything.