Do something like the following and you will notice that the callback of the button has nothing to do with the action triggered with the keybind.
Lua Code:
ZO_OptionsWindowResetToDefaultButton:SetCallback( function() d( "Hello World" ) end )
The only option i see is to hook into
ZO_Dialogs_ShowDialog( name, ... ).
I just don't think this is a really good idea unless you know all possible dialog names.