Actualy, I did scour around the source code, but I didn't like the arangement and the fact that I couldn't find the answer at that time's dillema on a first glimpse in the file (And I still can't find where the actors are forced out by the explosion XD ). So I assumed it would be pretty annoying for others like me to follow that code... that would be my mistake.
But still, copying code is one thing, writing it by yourself from hints is another
Later Edit: I just read the Explosion demo thoroughly (my head hurts

) and it's not even close to what I was thinking. Their solution is a lot smarter. It's a kinematic actor that has a selected list of other actors it can affect, is in form of a sphere and grows every frame, thus pushing objects in it's area. It stops after 100 frames... extremely nice
Thanks for actualy forcing me to read that! I'll almost surely use this solution.