I am not aware of any way to get the button facade support, but there is another approach which should achieve a nicer finish, even if it doesn't match the button facade skin.
The in-game icons can be replaced through placing equivalents into the game folder.
There are packages hosted on wowinterface where these icons have been created.
Clean Icons
Clean Icons - Square
AI-Art Icons
Since those replace the in-game icons, which are those used by powerauras, then it will change the appearance of those.