Quick Question Are you trying to Run the virtual 3D cockpit across multiple moniters or manually making the 2d panels fit. if your trying to run the 3d, may i Suggest you go to windowed mode and drag the one window across both screens then go back to full screen? that way all of the cockpit will be the correct view and not a moved one because if you change the camera angle, FSX only is gonna change one and you will have to reset the angles for it to be showing correctly.
Sorry if I Missed you trying this its early here.
MAIN: Intel E2160 1.8 GHz (Running 3.0 GHz Stable Stock Heatsink,), 6GB RAM SLI 8800GT's, OB 7.1 Sound, HDD's 120 GB, 80 GB, 250GB; 60GB Mac OSX 10.6 EXTERNALS: RCA TV Main, Dell E156FPb With touch panel (on keyboard drawer!), X52 Pro, R.A.T. 7 Mouse, Logitech G13, 5.1 Speakers, Creative Tatics 3D Headset,