Is it popping up the on-camera flash? If it is, you need to shoot in some mode, or otherwise persuade it, to not use flash!
Try shooting in manual mode, it SHOULD not pop the flash up. It should still tell the hotshoe that the shutter has fired, though, which should fire even a dumb flash. With a dumb flash you need to shoot manual anyways, the metering modes are all pretty useless. I guess except maybe for fill, but you'd have to do the fill part with a manual flash setting, and maybe tell the camera to slightly underexpose.