btns with sound different in as3?

In earlier versions of flash, I simply add the sound inside the button on a new layer setting the sync to event. When I use this same method in AS3, the overstate sound plays on the downstate as well. I guess one answer would be to just not put sound on the downstate. Listen closely and you can tell. The third button makes it very obvious. The only difference in these two files are the text that identifies the actionscript and the publish settings. Am I supposed to use actionscript to attach the sound when using AS3?

Here are the files.

http://www.pixelprof.com/images/btn_sound_as2.swf
http://www.pixelprof.com/images/btn_sound_as3.swf

right-click and save target:
http://www.pixelprof.com/images/btn_sound_as2.fla
http://www.pixelprof.com/images/btn_sound_as3.fla