With the ACE 2 mod soon to appear on the SimHQ servers, there's a file that you'll probably have to configure for yourself ... the ACE 2 keyboard bindings. They're found in your ArmA 2/userconfig/ACE folder. The file is called ace_keys.hpp. You'll have to find about 15 free keys which is tough because ArmA2 uses about 164 commands
Here's a little spreadsheet I made to keep track of what I have set in my ace_keys.hpp file. The settings themselves are not recommended since they're based around the other keys I have customised, but the chart at least shows you what commands are available.
The injury/bleeding/health/medic system is REALLY good in ACE 2 ... make sure your "Interact" key is working. I've seen posts about people having trouble with the default (Windows) key that the interact key is set to.
Also, don't forget to back up your ace_keys.hpp file in case a subsequent update overwrites it.