Inserts a 'shim' IFrame element to manage display of overlapped elements.

Parameters: Object reference (OSK outer DIV), Object reference ('shim' IFrame), Object reference (OSK inner 'Help' DIV)

Returns: Nothing

Note: The shim management functions are only used to support IE6 (which requires an intermediate IFrame element to display overlapping window correctly). They are ignored by other browsers, and may not be supported in future releases.