To import a new CA certificate into Thunderbird 1.5:

1. Launch Thunderbird and choose Account Settings from the Edit menu.
2. Select Security under the account name.
3. Click the View Certificates button.
4. Click the Authorities tab.
5. Click the Import button at the bottom of the screen.
6. Navigate to the CA certificate and import it.

To import a new CA certificate into Evolution:

1. Launch Evolution and choose Preferences from the Edit menu.
2. Select Certificates from the icon list on the left.
3. Click the Authorities tab.
4. Click the Import button.
5. Navigate to the CA certificate and import it.

To import a new CA certificate into Outlook:

Once you've imported a certificate into your IE browser, Outlook can access it from the same store, so there's no need to import it again. There's also no need to export it from Outlook since you can export it from IE.