web2py URL helper not building good URL's
===

I'm starting in web2py and I need to link my static files in my view files.

I'm trying to use URL() helper to make the links but I doesn't work properly...

My application is called red, my controller default and my function index.
My view is called index.html and is inside default folder, when I go to the page I see the view correctly but my URL are all wrong...

So far I tryed:

    URL('static', 'css/bootstrap.min.css')
which gave back: "/static/css/bootstartp.css"

    URL(a=request.application, args='static/css/bootstrap.css')
which gave: "/default/red/static/css/bootstrap.min.css"

    URL(r=request, arg='static/css/bootstrap.min.css')
which gave: "/index/static/css/bootstrap.min.css"

    URL('static/css/bootstrap.min.css')
which gave: "/default/static/css/bootstrap.min.css"

I may have tried some more but with no success...

My index function only returns dict().

And my router:

    routers = dict(

        # base router
        BASE = dict(
            applications = ['red', 'admin'],
            default_application = 'red',
            default_controller = 'default',
            default_function = 'index',
            map_static = True
        )
    )

I think it's also important to say I'm testing it on google app engine.