[Zope] UserFolder

hello and thanks for your help I want to sustitute authentificateCredentials for this plugin i made. It take users from ZODB and validate if user exists and so user can login in Plone. can´t I do one product pluging for PAS with one init.py and one ProductName.py where this method is implements for sustitute standar method??? Thanks I´m sorry for my english, i´m spanish.