Hmm...are you sure you set everything up correctly? You don't have to turn off the camera. You can target it, and in it (the camera)'s properties, set it to hold for however long. Don't bother targetting it again with the multimanager. If you already have set this, I have no idea what is causing the problem. Just make sure you set it in the correct box. Also, I think seconds in HL are shorter than seconds in real life, but that still doesn't explain it since you set it to 500. But if you set it to say, 10 seconds, it would hold for 10 HL seconds, and then stop. If you are targetting it a second time with the multimanager, don't. I've never tried it before, so I have no proof that it works (Or, indeed, doesn't work), but I know it works if you set the hold time correctly.