Controlling timeline of loaded movie

I’m loading movie01.swf into _root.movieHolder01, where movieHolder01 is an empty movieclip. At some point, I want to be able to gotoAndPlay frame 7 of movie01.swf (which is inside of _root.movieHolder01).

From the _root timeline, I’ve tried:

_root.movieHolder01.gotoAndPlay(7)

and

_level0.movieHolder01.gotoAndPlay(7)

The above didn’t work for me. How can I do this? Thanks.