Overloaded has_many_polymorphs method is still being called

I have a has_many_polymorphs class called Property. For the various
classes that are polymorphs, i've written a module with methods relating
to Property, that they can all include.

One of my methods is called 'add_properties': it creates some new
associations, but also does a couple of other things (such as update the
object's ferret index, and return a boolean instead of the added
objects).

However, it looks as if has_many_polymorphs generates a method called
'add_#{your h_m_p class here), which does the same sort of thing.
That's fair enough, but it's being called instead of the version in my
module. Shouldn't my own custom version of this method override the
h_m_p version? And can/should i go and strip the generated method out
of my local install h_m_p?

thanks
max