Authorization header using ActiveResouce

I'm trying to use ActiveResource in a ruby script to consume a web service that requires simple HTTP authentication. From the docs, this seems like it should be trivial:

require 'rubygems' require 'activeresource' #I'm on 2.1.0

class List < ActiveResource::Base     self.logger = Logger.new STDOUT

    self.site = 'http://myuser:mypass@mysite.com' end

But when I try to use the model, it throws back a 401--even though the same resource works just fine when invoked from a web browser. When I looked at the outbound traffic using WireShark, the Authorization header isn't even there.

Any hints/suggestions?

Thanks, Ben