WordPress custom permalink /%postname%.html only applies to posts, not pages?

When I change my permalinks to custom:

/%postname%.html

My posts are all开发者_Python百科 redrawn correctly to post-title.html, however, my pages do not get the .html extension (they just appear as if I had used /%postname%/.

Anyone know why and what I can do as a workaround?

Pages can have sub-pages, so I guess it makes sense for it to create a directory named after the page.

Is there any reason why you need the .html?