If you buy a live feeder and want to swap them to FT then be aware you should offer live for the first few feedings to make certain the snake is settled into his new home before adding any additional stressers.
There's tons of tips on how to swap them over and normally a BP set up properly will readily take a properly prepared FT rodent.
Some key things are that it MUST be fully defrosted, and then warmed. Using a hair dryer to spiffy up the heat signature just before offering it is also a good tactic. Don't be aggro with the prey item, no shoving it at his face, or shaking it vigorously over his head.