You can book flights on United.com that connect to Cape Air or Silver Airways (operates as United Express) to Key West -- through Ft. Myers, Ft. Lauderdale, and Tampa. But I called United and was told by the unhelpful, clueless Indian woman answering the phone that no award tickets could be issued on either of these airlines, so there was no way to book a ticket to Key West using miles? Is that correct?

(If it matters, I'd prefer to use US Airways miles but could scrounge up MP miles).