I can not reproduce the behavior.
To have recording source show up in Media Scheduler, you must have scanned (or otherwise manually created) a list of channels in Media Center.
The channels are saved in registry here:
HKEY_CURRENT_USER\Software\JRiver\Media Center 11\TV Settings\TV Channels
If you can find the channels there, I can not think of any reason why they would not show up in Media Scheduler.