What are you using for microphone? Stand-alone, or headset/mic combo?
On the joystick push to talk, there are basically 3 places where you MUST set up the mapped button on the joystick. First, in Setup on your clipboard in the game, go to key mapping. Pick a key on the keyboard and assign it to "Key_Mic". Try not to use a letter of the alphabet, or other common key used in chat (I use Tab). Click apply/ok. Second, you have to make sure the exact same key is designated in your RW setup. Third, you have to have the same button set as push to talk in your joystick software. I use a Sidewinder PP 2.
Even then, the setup will go haywire for me every time I shut down the game and restart it and RW. I have to alt+tab out and reassign the button in my joystick software, then reapply it. When I go back into the game, it works again.
I have no clue, never played H2H.