ROM Manager doesn't work with CF-Root, that's why you have the CWM app.
Exhashdotdot: yeah, grab KF3 CF-Root and flash with Odin.
Ah, that might explain things, although tried flashing it through cwm app and it failed to boot, unless it takes a really long time to boot (my magic used to take longer, but not as long as I just waited looking at the boot screen (one with the triangle on it)