Why Does WS Convert My Motion Menu PCM (.wav) Files To MPEG Files?

My WS project is made of M2V (NON MULTIPLEXED MPEG VIDEO) and seperate PCM (.wav) audio files. (All of which were created in Adobe Premiere 6.5 and rendered using the Adobe MPEG encoder 1.2)

When I burn the DVD disk, WS converts the motion menu to MPEG audio, and leaves the rest of the M2V files with their attached .wav files as PCM audio. HOW DO I PREVENT WS FROM CONVERTING THE MOTION MENU WAV AUDIO TO MPEG AUDIO?

I have no sync problems, and all the audio sounds ok, but I do not want MPEG audio on the DVD, let alone two different audio formats running on it.

I've checked all of the files and made sure all the correct formats are being used.

I have been keeping the Box "Do not convert compliant file" checked (as in no additional conversion. Is this the problem?
If I uncheck this box, will it convert all the audio to PCM or MPEG audio, and what would unchecking the box do to My Video, recompress it?

Please help.