Yosemite keyboard shortcut for "keep both" "stop" or "replace" when moving files in Finder?

When you copy or move files in the Finder in Yosemite and there is a conflict, a small dialog box pops up proposing:

keep both    stop    replace

(or "skip" if you press option).

However, I can't find any way to choose one of the options with the keyboard.

There's no default option. Cmd-R doesn't work for replace. Escape does nothing.

I've tried every combination I can think of and nothing works.

Are there keyboard shortcuts to choose these options?