Converting from AS2 to AS3

I 'm trying to convert a project [7. Cool Icons Set - Blue Glossy][1] from AS2 to AS3 (with Flash CS3).
It has some MovieClips.
In the MovieClips it has code. For example in some frame of a MovieClip it has ‘stop();’

But in AS3 code is not allowed in the MovieClips.
How can I do it in AS3? (I suppose I 'll have to make some class for the MovieClip…??)

Anyway, don’t you think this is a regression?
It was so easy to put code in the frames of the movieClip and so handy, and they replaced it with something much harder?
[1]: http://ntt.cc/2010/03/25/20-useful-flash-menu-button-with-full-source-code.html