"Click' and "Pop" menu sounds

[signal34]

I don't believe so, but you can add sounds to the %installdir%\BuildOS\USER_OEM\Additonal Sounds folder -- that will cook them into your ROM. Or just copy your desired sound bites into the PPC's Windows directory right now.

I believe, however, that if you want to add older sound bites to your cooked ROM, just place them in the Additional Sounds folder. You can use the same names as what's currently in the protected .RAR files, and when the ROM is being cooked, a menu will pop up asking you if you want to overwrite the default file (protected .RAR) with the one in your USER_OEM folder.