Creating and Using UniqueIDs in Shapes

Hello all,
I'm not new to Visio nor to programming but I am new to developing in Visio.
I'm using 2007 and am creating my own custom shapes with Shape Data.
I want to create a UniqueID for all my shapes in the context of the drawing.
I have created a Shape data element called 'Shape UniqueID'. (ShapeSheet  Prop.Shape_Unique_ID)
I tried to generate a unique ID (Shape.UniqueID property), using the formula syntax below, in the ShapeSheet 'Value' cell for the property : 
    =UniqueID(visGetOrMakeGUID)   and =UniqueID(1)
But Visio does not recognize this as a valid Formula..

I also tried to use DATA1():
    =Guard(Data1())
That gives me a unique value BUT it does not update if you copy the shape.

I've dowloaded the 2007 SDK and can't find a Shapesheet function to read the properties.

I have also seen that you can set the page so UniqueIDs are always on shapes used but I can't figure out how to turn it on.

My "preference" is to use a Shape Data element and set it BUT......
 
Any Ideas would be appreciated?
Thanks ... Scott