Your question has me interested.
For flip use:
Gui.ProcessCommand(32835) 'Draw Mode
' Some code that selects draw objects
' Anyone know how to set a tentative snap point using automation? (Do this here)
Gui.ProcessCommand(32830) 'Flip Vertical. use 32829 for horizontal
Any/all objects will be flipped with respect to the center of the bounding box of the selected draw items unless someone knows how to solve the problem mentioned in the second commented line.
You can pull up the popup to set the value: Gui.ProcessCommand(33837) but I have no idea how to change the value.
Maybe something with the CommandBarButton.Target property? According to documentation It is supposed to return a COM object.
Anyone else have ideas?