Can i modify Garamond Premier Pro to add diacritical marks?

Hi there

I run a small publishing house that intend to produce translations of Arabic works into English. I was looking at using Garamond Premier Pro as the in-house font, but it doesn't have the necessary characters with diacritical marks to transliterate Arabic into latin script. Does the license permit modification of some of the letters by adding a dot underneath them?

Thank you