Watching a Movie on iMac with ext. panel

[stoobz]

hey there,

is there any way to watch a movie on a screen, connected to my intel iMac coreDuo and meanwhile switch of the iMac-monitor?

I tried several scripts, that send the monitor to sleep after 60 sec. but also the external panel is switched off then

this really annoyes me, since my 6-year-old thinkpad does this with an simple fn-key...

perhaps somebody with the same problem wrote a little script?

or did anybody open their iMac to put a switch in between the screen-power-cables? if so I would appreciate any help, so I can try this on my own

thanks alot for any help in advance!