umlaute in selectbox

I've got a form.select that takes the choices from an array in the
model customer_adresse. When I write "ü" and "ä" in the
prompt and the keys of the array, I see "ü" and "ä" in the
selectbox. When I simply write these characters, I get quadrat signs.
The signs have ascii codes 129 and 132.

I've set "encoding: utf8", but actually, the database shouldn't be
concerned with this problem.

As I'm using Rails 2.0, I think I don't need to use
ActionController::Base.default_charset=("UTF-8")

I'm trying to use the parameter html_options, but nothing has
changed.

    <% form_for :customer_adresse, :url => { :action
=> :save_adresse } do |form| %>
          <%= form.select :bundesland, CustomerAdresse::BUNDESLAENDER,
options={:prompt => "Bitte w&auml;hlen Sie aus"},
html_options={'accept-charset' => 'utf-8'} %>
    <% end %>

  BUNDESLAENDER = [
    # Displayed stored in db
    ["Baden-W&uuml;rttemberg", 1],
    ["Bayern", 2],
    ["Berlin", 3],
    ["Brandenburg", 4],
    ["Bremen", 5],
    ["Hamburg", 6],
    ["Hessen", 7],
    ["Mecklenburg-Vorpommern", 8],
    ["Niedersachsen", 9],
    ["Nordrhein-Westfalen", 10],
    ["Rheinland-Pfalz", 11],
    ["Saarland", 12],
    ["Sachsen", 13],
    ["Sachsen-Anhalt", 14],
    ["Schleswig-Holstein", 15],
    ["Th&uuml;ringen", 16]
  ]

It seems that my files must be in utf-8. I've set the charset of the
view to utf-8, so the umlaut in the prompt is displayed correctly.

The problem seems to be that rails can't deal with models in utf-8
charset. I get a syntax error when I set the charset of
customer_adresse.rb to utf-8.

Any idea how to handle this?

Thanks
Luma