Problems with :onchange for radio_button_tag


I've been hitting my head to the wall over this for quite a while now and don't seem to be able to wrap my forementioned head around it. Basically I have a list of users in a selection box and I have two radio buttons: Sort by first name and sort by last name. This is what I have in my view:

<%= radio_button_tag 'sort_by_last_name', 'true', :checked => true,         :onchange => '#{remote_function(:url => {:action => "update_users"},         :with => "order=1")}' %> Sort by Last name<br /> <%= radio_button_tag 'sort_by_last_name', 'false',         :onchange => '#{remote_function(:url => {:action => "update_users"},         :with => "order=0")}' %> Sort by First name

<div id="users"><%= render :partial => 'users', :object => @users %></div>

This is my partial view: <%= collection_select(nil, :user_id, users, :id, :first_name,                      {:prompt => "Select user"}) %>

And this is my controller function for update_users:

def update_users    if params[:order] == 1      users = User.all    else      users = User.first    end

   render :update do |page|      page.replace_html 'users', :partial => 'users', :object => users    end end

Now I've found a few sources describing on how this should be done, but I haven't been able to get them to work for some unknown reason.