Safari 5.1.7 (from Apple)

Importing SSL Client Certificates

• click on the gear icon on the top bar
• in the lower third of the menu select "Preferences..."
• select the "Advanced" tab
• next to "Proxies:" click on the "Change Settings..." button
• in the "Internet Options" pop-up window click on the "Content" tab
• in the "Certificates" section click on the "Certificates" button
• in the "Certificates" pop-up window click the "Import..." button
• in the "Certificate Import Wizard" pop-up window click the "Next >" button
• browse to the directory where your certificate file is (PKCS #12 files) (e.g., 'joe-at-dummy.org.p12')
• in the "Open" pop-up window click on the "X.509 Certificate (*.cer;*.crt)" button and select "All Files (*.*)"
• highlight the desired file and select "Open"
• click the "Next >" button
• in the "Password" dialog window enter the certificate password (provided by the site admin or CS Rep) and click the "Next >" button
• in the "Certificate Store" dialog window click on the "Next >" button
• in the "Certificate Import Wizard" window click the "Finish" button
• click the "OK" button to dismiss the "Certificate Import Wizard" window
• click the "Close" button to dismiss the "Certificates" window
• click the "OK" button to dismiss the "Internet Options" window
• click the "X" in the title bar of the "Advanced" window to dismiss it

Then the certificate import process is complete.