Mongrel Upload Progress conflicts with :controller/:action/:id routes

Has anyone using Mongrel Upload Progress ran into issue with Rails
default routes like post/add/1, where 1 is the ID of the post to add?

The problem is, MUP requires that you specify the path to observe as:

    :path_info => ['/post/add'],

However, this wouldn't match the path "post/add/1" since the "/1" was
interpreted as part of the path. What can I do to work around this
limitation?

Thanks,
Eric