Preloading external SWF into movieclip on main.swf

for some reason this seems to be a hot topic recently. yet all the documentation seems to point in other directions…

i have a preloader that works well for the main.swf, yet i have an external swf the needs to preload between two scenes but yet still play in the main timeline (it´s complicated why i just can´t preload in the beginning, but i has to do with user input).

i´ve been thinking simply to create a movieclip where i need to it play, and preload the external swf into that. yet i´m at a loss of how to script and what to do.

any help is appreciated! thanks.