Navision web service with kerberos authentication

I have setup a 3-tier configuration of Navision and access the Navison web services from two places: from the application server and from a client computer. The call on the application server uses fixed network credentials (not the default credentials) and works ok.

On the client computer i want to use the credentials of the logged on user. I want to use the kerberos authentication.

The only way i seem to get it working is to add the the service principal name to the config like:

<endpoint address=....>
   <identity><servicePrincipalName value="...."/></identity>

Is there an alternative, so i don’t have to specifiy the SPN at the client side?