Rails - Jun 2006 - url_for missing out parameters?

Having a bit of an issue with url_for

The current page I''m on has a named route as follows:

map.some_page ''page/:id/:range'', :action =>
''the_action''

All looks fairly normal. I have an url_for on this page to make a link 
to another page as so:

url_for(:controller=>''other'',
:action=>''display'', :id=>5,
:range=>''the_range'')

This URL comes out as:

/other/display/5

You''ll note that the ''range'' is missing.
Passing in anything else other than ''range'' works fine.

IE:

url_for(:controller=>''other'',
:action=>''display'', :id=>5,
:test=>''something'',
:range=>''the_range'')

results in:

/other/display/5?test=something

Any ideas why it''s ignoring the ''range'' param?

Removing the :range param on the named route for the current page (note, 
not the page the url_for is pointing *to*) make it work, but then that 
breaks the nice url in the current page!

I''m running edge on windows with ruby 1.8.2.

Thanks in advance.

-- 
R.Livsey
http://livsey.org