Alright, so I'm using an Infocus LP640 to project onto a 100" screen I just purchased. My current issue is that when I hook up the DVD player to the projector using a regular composite video cable, the actual image keystone can be altered so that that image is rectangular, but the total projection area stays trapezoidal. How can I fix this so that the actual screen fits perfectly onto my 100" screen? Thanks in advance, Josh P.S. I'd bet it says something like this in the user manual, but I purchased the projector used from a friend with only the projector and power cable.