Help with Stimulus DLC

So i bought Stimulus DLC on legal MW2, now how the hell do I choose maps myself, as they say u can... Pressing F4 doesnt show up a popup to me...

HEEELP

just because you bought stimulus you are not able to choose maps. you have to use vac chaos to set maps...

Hold on, did you buy MW2? If you did, pressing F4 doesn't do anything! If you want to play DLC maps, you click 'Stimulus' on the gametype list. Pressing F4 is for VAC Chaos and unless you want your $15 come to waste, I'd stay away from VAC Chaos if I were you.