I haven't tried, but you might want to give these guys a call.
They're a scuba diving company. Lessons, gear, etc. They do tank fills. You might be able to talk them into filling your tank up for a fee. Otherwise, you'd have to use your own compressor/scuba tank or fill it up at a field, however I believe most, if not all fields are closed for the season. It's too bad we don't still have Warped Sports around anymore. Those were the days