problems assigning a shortcut key to a macro

[Bhikkhu Santi]

I read an explanation of how to set shortcut keys for Pali diacriticals by Bhikkhu Pesala. So I've made a macro for inserting each character and now I'm trying to assign a shortcut key to it, either by 'assign' or 'customize'. Either way I can't create a new shortcut key combination, there's only a very limited list of shortcut keys. So far I've been using Alt + character or Alt + Shift + character in MS Word because then I don't lose any of the shortcuts I'm familiar with and can have a logical consistent system which is easy to remember for all the diacriticals (special characters).

Does anyone know how to add new shortcut keys to the list? Especially beginning with Alt, because I never use that key otherwise. I need about thirty shortcut keys, preferably unassigned and preferably in a logical memorable order.

Thanks, Bhikkhu Santi