Hello,
I know it's been a month for you, but I just got my first Raspberry Pi and have been trying to get it to run my OTA as well.
Are you in the US? My guess is yes. From what I've read it's a bug that was fixed in some development code, but was never pushed to the stable version, and its a bug that plagues a lot of people. I too suffer from the "services found, but no data" bug. From what I can figure we can not map channels because the services do not have channel data with them. I get that channel data if I use w_scan however so that is quite frustrating.
One thing you can do for the time being and I'm not saying this solves anything, is to manually add a channel name onto the service. This will at least get the channel available in XBMC (OpenElec) to watch, but you have no epg data with it. So far I've been closest to having live tv running with tvheadend so I'm going to keep trying.
I know this doesn't help too much, but hopefully it gives you a glimmer of hope. I'm gonna keep hunting down a solution to the problem.
Best of luck,
TraumaER