IIS/Unicode and authentication box

[vladimir () arobas net (Vladimir Parkhaev)]

I am trying to show to a customer that his IIS server is vulnerable 
to unicode exploits.  However, access to his server is password protected
(Require valid-user) I get "HTTP/1.1 401 Access Denied" and 
"You are not authorized to view this page".

As far as I am concerned, having password box does mean he does
not have to patch his web server. How can I show that his box
is vulnerable? Anybody? 

-- 
print chr hex for qw +
2D 2D 0A 76 6C 61 64 69 6D 69 72 40 61 72 6F 62 61 73 2E 6E 65 74 0A 44 38
37 44 20 44 32 46 42 20 46 31 36 33 20 46 31 43 31 20 34 32 30 41 20 20 31
44 31 46 20 36 43 42 39 20 31 46 38 39 20 38 35 30 42 20 30 38 44 44 0A +;

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