Obs.: In my latest mods you can edit the hotkeys for Keyboard and for Controller using the Controls menu in the mod menu or in the mod Options menu :)
If the hotkey generates issues when pressed because it calls a game action like aiming or get in cover, you can disable the game action in that menu pressing T or the indicated button in the bottom of the menu.
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In great part of my mods you can edit the self-generated .ini file (gta Scripts folder) and change hotkeys for keyboard and sometimes for XBox control too.
This is the list of keys that you can use to edit the keyboard keys:
http://msdn.microsoft.com/library/system.windows.forms.keys.aspx
Let me show a example, in Max Payne IV we have this on .ini file:
hkActivate is the hotkey to activate the mod, to change it to Middle mouse button for example you change it to:
hkActivate=MButton
Save the file, reload the game and done!
Check how to change XBox controls here.
