##Rails routing issue

map.normal_thing 'things/:id', :controller => ... whatever
map.uuid_thing   'things/:uuid', :controller => ... whatever

@thing= Thing.find(1)

>> normal_thing_path @thing
=> "/things/1"

>> uuid_thing_path @thing
=> "things/1"

##@thing has a :uuid property. How can I get this to act how I want it too?