NewScene , false 
set oRoot = ActiveProject.ActiveScene.Root
set oGrid = oRoot.AddGeometry( "Grid", "MeshSurface" )
set oGeom = oGrid.ActivePrimitive.Geometry
set oClip = oGeom.SaveShapeKey(1)
set oPSet = oClip.AddProperty( "CustomProperty",false,"ClipData" )
oPSet.AddParameter3 "StringOnClip", siString
' You can also store binary data
oClip.AddProperty "UserDataBlob",false,"MyBlob"
' The new properties show up on the bottom
' of the PPG
InspectObj oClip