Clip loading at a certain frame

Hi everybody! Thanks for looking at my question.

I have a slide down menu ( i made it by making a box a movie clip and editing the movie clip so it just slides down.

And i wanted buttons to load (from an external swf) as soon as the menu goes down.

For instance, the sliding movie clip instance is a. A moves down and stops at frame 15. This is when i want the buttons to load from the external swf. And i want it to load in the box not on the main movie even though i guess it doesnt matter since now the box is over the main swf anyway but regardless i hope im not confusing anyone.

So anyway, I was wondering how i could do this. Thanks for your help and i hope i was clear on my problem

-Aaron