What kind of station is this and what's the nature of the program you're producing? Are you producing a program for the station or are you trying to sell a program to the station? If it's the former, the station should use its own captioning service and shouldn't burden you with that task. If not there are plenty of captioning services out there that will caption your program. Another thing, if you are selling your program to the station, then they shouldn't require you to caption the program at all.