SMB print with Kerberos

Hi there, I am deploying a printer Via MCX which works fine. however the machines are using an LDAP kerberos authentication setup. If i manually set kerberos on the machine using the following steps it works fine. [CODE] Open "http://localhost:631/printers" in Safari. For each printer you wish to share using Kerberos: Click the printer name in the list. Choose "Set Default Options" from the "Administration" pop-up menu. Click "Policies". Choose "Kerberos" from the "Operation Policy:" pop-up menu. Click "Set Default Options".[/CODE] The problem i have is I can't do this on each machine manually. This setting is not held in the PPD for that printer. I have set the option, copied the PPD from /etc/cups/ppd and then created a new printer using this PPD but the option is not enabled. I can see that when you enable this option it is writing to and then deleting the following files /var/spool/cups/cache/printername.png /var/spool/cups/cache/printername.data.N /var/spool/cups/cache/printername.png-psHg /var/spool/cups/cache/printername.data I am sure this is what is setting the option but i can't see anything in lpadmin or lpoptions that would allow this to be set via the command line. Any Ideas?