Thanks a lot, Midi Thief. But I have the same result as herbocarn. Using only one app at the same time, but still it didn't work. Also the photobooth can automatically hook up the hdv, which means the setting and connection is working fine, yet the Modul8 cannot recognize it.
I think I'll use an external HQ webcam instead.(which works perfectly well in Modul8)
and maybe try some different types of camera see if it works.