Rails acts_as_* plugins, with parameters

Hi all,
I'm trying to write a plugin which will allow me to specify:
acts_as_item :option=>:value

i need to be able to access the :options=>:value hash from instances of
the model also.
I've tried with class_eval in the plugin, but can't get it working.
I'm calling acts_as_item(options), and that method can see the options
passed from a model. Then inside the class_eval, I'm adding a method
(def self.configuration) which returns the options hash. I thought from
an instance, I'd be able to do instance.class.configuration which would
then return said options hash.

Any ideas?
thanks for reading.

module Item
#called by active record for us
def self.included(base)
base.extend ClassMethods
end

module ClassMethods
def acts_as_item(options = {})
configuration = {:option=>:value}
class_eval {
include InstanceMethods

     def self\.configuration

I think you want this to be
            def configuration

Since this is in a module extended by the class.