Control main timeline from external loaded swf

Hello to everyone,

i am trying to build an image gallery with as3 and i have one problem.

In my “main project” i load successfully different external swf’s files. But in one swf file
i have some buttons which i want when i press them to change the scene of my “main project”. I cannot succeed this interaction.

Can anyone give me a very simple example with code so i can use it like a guide line?

I googled but i found some stuff that confused me.

Thank you!