Cruise Line Air Fares

The air fares charged by cruise lines even though they include transfers are always higher than the open rates. I am always able to find much lower fares through consolidators or Orbitz/Travelocity. The problem is two fold. 1. They require payment within a few days of the booking. 2. Consolidators do not have contracts until 6 -9 month prior. As most of the cruises I sell are booked with deposit 9-12 months before sailing how can I achieve what the cruise lines do. That is, hold space but do not have to pay until 90 days prior to the cruise date. I would not mind charging the client a $100 deposit fee for the air with cancellation penalty. Any advice would be appreciated.