wsdl not generated when using "expects"

I have a class that extends ActionWebService and is able to generate a
wsdl (http://localhost/mycontroller/service.wsdl) when api_method
doesn't have any parameters. As soon as I add/define a parameter I
get:

Template is missing
Missing template ./script/../config/../app/views/mycontroller/
wsdl.rhtml

Here is the controller followed by the api class:

class MyyController < ApplicationController

web_service_scaffold :invoke
  wsdl_service_name 'myservice'

def foobar(someparam)
return "test"
end
end

class MyserviceApi < ActionWebService::API::Base
  api_method :foobar , :expects => [{:someparam=>:string}], :returns
=> [:string]
end

I am running rails 1.2.3, any idea what might be causing this?