F5 with websense with Kerberos authentication

Hi,

I reccently moved to F5 LTM module and I want to configure my F5 to work with my WEBSENSE PROXY's servers with kerberos authentication. I setted up all the proxy servers to work fine with kerberos authentication and I get a ticket successfully when i sufring through each one of them. The problem is that when I surfing through the FQDN of the VIP that is configured on the F5 iApps VS I dont get a ticket and thhere is fallback to NTLM. It seems that the F5 doesn't forward the kerberos request

What is the special configuration I need to do on the F5 wo the kerberos will work successfully

Please Help !!