Ok, took me a while, but here it is.
First, you need to add "-dev" to the command line in your CoH shortcut.
Next, when in game, press SHIFT+CTRL+~ to bring down the console.
And finally, type "setsimrate(#)" where # is the speed at which you would like the game to run. I believe 10 is the default speed so typing "setsimrate(5)" would make the game run at 50% speed. And it does. Finally you can see all them firefights in slow motion.
P.S. this is actually a console command for DoW, seems they haven't changed it. In DoW however, you could also use in it multiplayer, if the game master allowed it... since CoH has no such option, I wouldn't try this in multiplayer (don't know even if it would work, haven't tried) because it can lead to out-of-sync problems and screw up your game.