2405FPW not turning off it's backlight when in screensaver?

I've got a 2405FPW connected to a KVM, using the analog SVGA connector.  When any of the PCs on it go into a blank screensaver mode the display does not turn off it's backlight.  This is true across XP, windows 2000 and linux.  What is necessary to get the monitor to kill it's backlight? 

I should add that I've confirmed it's loaded the latest driver (in w2k and xp anyway) and the hardware is recognized as a 2405FPW (analog).  The display power management settings are enabled.  In windows the display control panel is set to the "Blank" screensaver with a 5 minute setting.  The Power setting is configured to turh the monitor off after 10 minutes.  The screen blank part works fine, the screen goes black.  But after no amount of time does the LCD ever turn off it's backlight.