sending basic auth credentials with request

[lsiden]

I need to get Webrat::Mechanize to log onto a site that returns a 403
even when you go to the welcome page (it's not for the general public,
but the client must use a shared-hosting site).

First I attempted to use the login form but that did not work, because
Webrat does not create a scope object when it sees the 403, even when
there is content.

Martin Emde already recommended on the forum that I try basic
authentication. I tried doing it like this:

... do |site, user, pwd|
basic_auth(user, pwd)
visit site
...
end

but it throws an exception:

403 => Net::HTTPForbidden (WWW::Mechanize::ResponseCodeError)

I suppose I would see this if I were passing an invalid username and/
or password, but I already double-checked this manually in the browser
and I'm passing the right credentials.

I'm obviously doing something wrong, but I need an example to go on.
Can anyone point me to an example?

[lsiden]

A bit more info. In webrat.log, I've got:

D, [2009-11-23T14:14:06.042501 #12946] DEBUG -- : REQUESTING PAGE: GET
https://gator1087.hostgator.com/~tes/admin/ with {} and HTTP headers
{"HTTP_AUTHORIZATION"=>"Basic dGVzOnRvdGFsZXF1aXR5MQ==\n"}

I'm not sure what "Basic dGVzOnRvdGFsZXF1aXR5MQ==\n" means at the end
of the log message. Is that a hash of the username and password. Is
something supposed to be on the right side of the '=='? All I can
find on the subject is this: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.8.
What is the request header supposed to look like?