layouts in Rails 2

i'm having a little problem coming up with a dry way to use a layout
for multiple content types

i am using Mime::Type.register_alias 'text/html', :openid

in my layouts folder i had application.html.erb, so i changed it to
just be application.erb. that works for html requests, but anything
marked as openid doesn't display the layout at all. for now, i am
having to duplicate the layout and have application.html.erb and
application.openid.erb

any help is appreciated. thanks.