How to aet audio type

[yikchin]

i want to create a DVD for drama. the movie file is VCD (.dat) based.

In "Project Setting", i go to "Change MPEG Setting" and "Custom".

Next, i select "Compression" tab and select "Dobly Digital Sound" in "Audio Setting".

the problem is, i cannot modify audio type file ...

anyone can help me so that i can modify "Audio Type" . Thank you ..