Try using http://www.autohotkey.com/ with the following script:
^!b::
MouseClick, left, , , 1, 0, D
Sleep 5000
MouseClick, left, , , 1, 0, U
return
This will click the left mouse button for 5 seconds when pressing ctrl-alt-b.
This is regardless of inputdevice. To find out which keycode your device sends use the built in "Key history and script info" and replace the "^!b::" with the keycode found, ex: "SC132::".
More information about MouseClick http://www.autohotkey.com/docs/commands/MouseClick.htm
I've been able to work out that Button 0 and Button 1 are actually Left and Right Mouse (may be the other way around)
These can be assigned at the Controls > Customize Controls screen by clicking the Attack Hand/Open hand options and double left/right clicking (as you need to left click to start the assigning process)
Then, by using space for legs and E for head, the main controls sort of work ok.
I'm Currently using:
1-4 Weapon Change (sword, hidden blade, etc)
Space Legs
E Head
Left Click Attack Hand
Right Click Open hand.
That way, I can loot/attack mostly with the mouse. Pressing and holding W (up), E (head) and Space (legs), and directing myself with the mouse, gets me up and over rooftops ok.
I've only gotten to an early part of the game, so I haven't had time to perfect my keys. I'll update this post when I do, and let you know what is the best key arrangement (in my opinion).
UPDATE: The above works well, with Q/F in use for locking, etc.
This should be valid for AC:B too.
Best Answer