To answer my own question:
I created a new module including my methods and extended each unmarshalled object of Product::Feature
with it. This looks like the following:
module FeatureExtension
def my_method
# do something
end
end
Somewhere after I received a Product
from ActiveResource
I used the code:
@product.features.each do |feature|
feature.extend(FeatureExtension)
feature.my_method # Now it is possible to call the method
end