I would also like to understand how to do the same the other way around too, such as accessing a variable (or executing a function) defined in an Edge composition from outside of it. For example, I have a function called "init()" within my "creationComplete" even on the main Stage. Is it possible to execute this method from outside of my Edge composition?
I am also interested in this.
You should be able to both call a function defined in the document DOM as well as call into the composition and call a function. Here's a sample that calls into the Animate composition. If you have access to sym, you should be able to call a function within the sym. One easy trick is to assign your function to a variable, then you can use .getVariable() to just get a link to the function itself.