Graphics How do I put a different images on my 4" lcd screen

Ok here is a riddle for you folks
I have a 4 inch lcd monitor that is used to hook up the playstation 1 and whatever else you want. I usually hook my portable vcd player to it on trips and watch movies I rip but anyways...My video card is a ATI All in Wonder 7500 Radeon I currently have the lcd screen hooked up through my video out on the back of my computer and it displays whatever is on my 17 inch monitor(mirrors it). What I want to do is set it up so that when my winamp visual plugin is running it displays full screen on my 4 incher but not full screen on my regular monitor so I dont notice it. I know there is something called hydravision but I'm not sure what to do if it is possible. any help is welcome thanks!