Import a new root CA into KMail

Hi,

I've switched over to using KMail for my work email, using LDAP for 
storage/retrieval and SMTP for sending.  The only way to access either 
remotely is over TLS, but the server certificates are signed using an internal 
CA.

How can I import the CA certificate so that KMail stops warning me about 
invalid certificates?  Although I've managed to get the certifcate imported 
into Kleopatra, it shows up under "Other Certificates", not "Trusted Root 
Certificates", and KMail continues to warn me about the server certificates 
signed by the CA.

--Mike