Controlling screensaver options w/GPO

I need to be able to control the settings for the 'My Pictures Slideshow Screensaver' using a GPO. The enable screensaver settings (available in the system.adm file) are set in the local GPO to use 'ssmypisc.scr' as the default. I have created an additional adm file to properly set the registry for the several of the 'ssmypics.scr' options but it still doesn't work.

;ssmypics.adm

CLASS USER

CATEGORY !!MYPicsSlideShowScreensaver

KEYNAME "Control Panel\Screen Saver.Slideshow"
POLICY !!MYPicsSlideShowScreensaver
EXPLAIN !!MYPicsSlideShowScreensaver_Explain

PART !!ImageDirectory EDITTEXT
VALUENAME ImageDirectory
MAXLEN 128
REQUIRED
END PART

PART !!DisableTransitions CHECKBOX
VALUENAME DisableTransitions
VALUEON NUMERIC 0
VALUEOFF NUMERIC 1
END PART

PART !!AllowStretching CHECKBOX
VALUENAME AllowStretching
VALUEON NUMERIC 1
VALUEOFF NUMERIC 0
END PART

PART !!AllowKeyboardControl CHECKBOX
VALUENAME AllowKeyboardControl
VALUEON NUMERIC 1
VALUEOFF NUMERIC 0
END PART

PART !!ChangeInterval NUMERIC
VALUENAME ChangeInterval
MIN 6
MAX 240
DEFAULT 6
SPIN 1
END PART

PART !!MaxScreenPercent NUMERIC
VALUENAME MaxScreenPercent
MIN 0
MAX 90
DEFAULT 90
SPIN 10
END PART

END POLICY

END CATEGORY

[Strings]

ImageDirectory="Use pictures in this folder:"
DisableTransitions="Use transitions between pictures"
AllowStretching="Stretch small pictures"
AllowKeyboardControl="Allow scrolling through pictures with keyboard"
ChangeInterval="How often should pictures change"
MaxScreenPercent="How big should pictures be?"
MYPicsSlideShowScreensaver="My Pictures Slideshow Screensaver"
MYPicsSlideShowScreensaver_Explain="Explained"

I've used gpresult to ensure that the registry is being set but it is still not controlling the screensaver options.