force detect displays

i usually use osx server (leopard) via remote desktop, but sometimes i need to use a monitor, but if i switch the monitor to another computer after a while the non connected osx server assumes no monitor is connected and when i switch the monitor back to it nothing happens? and the detect displays option is gone from system preferences because it doesnt think there is a display.

any solutions would be good as logining out doesnt sort it so i have to reboot evrytime and its very very annoying.

is there a command line detect display trick?

thanks