When your certificate is issued, you will receive an email with a ZIP file attached. Within the ZIP file, there is a file which ends in .cer - this is your certificate. Extract the .cer from the ZIP file and save it locally.
Next, go back to the NetScreen web administration interface and select the "Options" menu, then "Object", and then "Certificates". Click the radio button to load a "Cert" (certificate). Click the "Show" drop-down box and select "Local". Browse to the location where your .cer file was saved and click "Load".
There is no reboot required to complete the installation. However, verify that your VikingCloud Digital Server certificate was loaded as a "Local" certificate rather than a "CA" certificate. If it is showing up as a "CA" certificate, you need to reconfigure the NetScreen and set up the domain name again.