I just made a dummy booking on the new FP (1.5 cents/point) site. It appears that, if you don't have enough points to cover the full fare cost, you are SOL. (Putting it another way, FP does not allow you to combine cash and points when purchasing a ticket. This is a competitive disadvantage, since the Citi TYP redemption site does allow you to combine case and points to pay for a ticket.)