+1  A: 

I see this is normal. You may learn more about the conversation between client and server from this KB article,

http://support.microsoft.com/kb/264921

Then you will know why those 401 messages were there.

Regards,

Lex Li
ok, so it tries the other authentication methods first, isn't there a way to solve this?
Sem Dendoncker
I am not familiar with Spring.NET but you should be able to specify a credential which contains user name and password. You can search Spring.NET documentation for hints.
Lex Li