Safari: How to handle invalid security certificates ?

When accessing for the first time Community Single Sign-On (CSSO) enabled web sites like

• https://idp.e-taxonomy.eu
• https://dev.e-taxonomy.eu/trac/

Safari will display a warning window indicating that it can not verify the identity of the website. To not get this message everytime yu restarted Safari follow these steps:

1. Click on "Show Certificate"
   
2. Select the checkbox next to "Always trust ..."
   
3. Click "Continue"
   

The warning should not show anymore.