Not to sound too patronizing, but the most common reason that the polishing pad isn't polishing the glass is that you aren't using cerium with the pad.
The Synthetic felt and LP materials are simply carriers for the cerium. The friction between the cerium and the glass is what causes the polish. Too much water and not enough cerium can prevent the glass from polishing, as can too much cerium.
Play around with the amount of water you're using and the amount of cerium.