HELP! path issue from main swf to external swf

Any help would be appreciated.

I have my main swf that has a container called “mc_dropphotos” where I have:
[COLOR=red]loadMovie(“photo_scroll.swf”,_root.mc_dropphotos);[/COLOR]

[COLOR=black]In the photo_scroll.swf there are movieclips that I want to get the x coordinate of and do something in the main swf by:[/COLOR]
[COLOR=red]if (mc_dropphotos.mcPhoto1._x < -4.15){[/COLOR]
[COLOR=red]etc.[/COLOR]

[COLOR=black]which is the path syntax I thought you use for checking properties from an external swf. I have tried _root.mc_dropphotos.mcPhoto1._x , _root.mcPhoto1._x, _root.mc_dropphotos.mcPhotos.mcPhoto1._x, mc_dropphotos.mcPhotos.mcPhoto1._x and none of them work either.[/COLOR]

Any suggestions? Thanks!

p.s. the mcPhoto1 movieclip is in another moviesclip in the secondary external swf and is called mcPhotos.