Are the Canon extenders compatible with the 100L Macro lens?

[Narcolepsy]

In lists of lenses compatible with the 1.4x and 2x Canon extenders, I don't see the 100mm 2.8L Macro....
Is this because it would be an unusual (stupid?) combination, or because they don't work together?
Thanks

 

[Random Orbits]

The 100L is not compatible with Canon extenders. The rear element is not recessed enough.

 

[wickidwombat]

works great with the kenko ones though or since its macro you can put an extension tube between the canon extender and the lens for use in macro since maximum focus distance is a non issue