Eagle,
Since you are using CH sticks, why not use the CH Control Manager software in mapped mode?
The CM's "Record Keystrokes" function is quite capable of sending the "Enter" keystroke that you need.
The only downside with using the CM, is that when you install the CM software for the first time, Windows will re-detect your sticks and install drivers for each "Control Manager Device" (Fighterstick, Pro Throttle, Pro Pedals, etc.) in the order that it detects them being plugged in.
When it is done installing, it will have re-named all your CH sticks to Control Manager Device 1, Control Manager Device 2, etc., so you will probably need to re-map the sticks within AH.
Next, create and save a stick map for AH using the CM. The only keystrokes that you will have to record and assign to a button are those commands like the "Enter" key that have no direct in-game equivalent. The rest can still be mapped in-game.
I use a CM map for AH that leaves all the buttons set at the default DirectX buttons but adds labels that I can refer to if I ever forget what button I have mapped to a particular function.
If you like, I could modify my map to your requirements and then email it to you. Then, just start the CM, open the .map, and hit the download button to load it into your sticks. Start AH and you should be in business.
Let me know.
CptA