Quake 4 and twinview

[Michele Concina <psycosm1981@yahoo.it>]

I've just installed quake 4, i've started it but it show me the game on 
both my monitors..how can i configure it to play just on one?
With enemy territory i don't have this problem, but anyway i post my 
twinview configuration..maybe there's something wrong there:

Section "Device"
        Identifier      "NVIDIA Corporation NV43 [GeForce 6600]"
        Driver          "nvidia"
        BusID           "PCI:1:0:0"
        Option          "TwinView"
        Option          "MetaModes"     "1280x1024, 1280x1024; 1280x1024"
        Option          "SecondMonitorHorizSync"        "31.5-69"
        Option          "SecondMonitorVertRefresh"      "47.5-125"
        Option          "TwinViewOrientation"   "LeftOf"
EndSection



I've tried with both metamodes..it doesn't work!
Thank you for any suggestion,
michele