ActiveResource and file uploads

I am trying to figure out how I could ActiveResource with one of my
web services. I have a desktop application which basically sends and
receives data to and from the server via AMF. (It is an Adobe AIR
application for multiple platforms.)

I’m using RubyAMF as the remoting gateway and Rails v 2.2.2 as the
base of my web application.

I’ve managed to get file uploads work with ActionPack and save the
entries into an ActiveRecord model, but I also need to get file
uploads work.
After some research I couldn’t find relevant tutorial and/or post on
the net. Also, Also, I’ve read somewhere that ActiveResource does not
support multipart type data… That’s not too promising either.

Anyone has experience with this approach?
Thanks in advance.