Rfacebook + attachment_fu - path question

Hi all,

I’m trying to use attachment_fu with a facebook app - I have a challenge
when I go to call an image:
<%= image_tag @photo.public_filename %> renders:

This is because the way I have my facebook set up is to always prepend
the path with /my_app_name/

I added this to environment.rb as specified in the rfacebook tutorial on
Liverails:

ActionController::AbstractRequest.relative_url_root = “/my_app_name”

any ideas on how to get around this?
Thanks,
Dustin