i'm trying to get the iphone handle package working but by now without any success....

When i try to connect to <server>/<path>/json.pl I receive "error 401 Authoritation required" from the iphone app
I've otrs 3.1 installed on windows
authentication is based on active directory and single sign-on (perfectly working for web interface index.pl and customer.pl)
apache configuration
<Directory "C:/OTRS/OTRS/bin/cgi-bin/">
<Files index.pl>
Require valid-user
SSPIAuth On
SSPIAuthoritative On
SSPIDomain stf_nt01
SSPIUsernameCase lower
SSPIOfferBasic On
</Files>
<Files customer.pl>
Require valid-user
SSPIAuth On
SSPIAuthoritative On
SSPIDomain stf_nt01
SSPIUsernameCase lower
SSPIOfferBasic On
</Files>
<Files json.pl>
Require valid-user
SSPIAuth On
SSPIAuthoritative On
SSPIDomain stf_nt01
SSPIUsernameCase lower
SSPIOfferBasic On
</Files>
Could anyone help me on fixing this issue? I would use the same authentication method I've already implemented and perfectly running (AD+ SSO)
Thanks everybody in advance