collection_select and remote_function used together?

Hi there
I have this code
<%= collection_select 'address', 'address', @addresses, :id, :address, {},
        { :onchange => remote_function(:url => { :action =>
'show_order', :controller => 'addresses', :id => @user },
                                      :update => 'adrdiv') }%>

the @user id is passed but not the address id of the picked option in the select
how do I pass both at the same time?

thanks in advance