evolution and certificates

[Gerhard Magnus]

I've been using evolution to download e-mail from my ISP using
POP without problems.  Now I keep getting this message:
         
         SSL Certificate check for agora.rdrop.com:
         
         Issuer:            E=support at cacert.org,CN=CA Cert Signing
         Authority,OU=http://www.cacert.org,O=Root CA
         Subject:           CN=pop.rdrop.com
         Fingerprint:
         09:54:74:4b:b2:e4:32:a1:d2:56:e3:ac:34:de:cc:48
         Signature:         BAD
         
         Do you wish to accept?
         
         I reply "yes" and get the password window as usual.  But I'd
like to get rid of this message and learn something about certificates.

	The tech at my ISP wrote: 
"I updated the certificate (which expired) with one 
signed by the CACert certificate authority instead of using one I 
generated myself.  You probably went through this a year or two ago and 
"accepted permanently" then.  The Signature is "bad" because you don't 
have the cacert root cert installed.  I'm not sure how to install the 
cert so that evolution will use it, but info on getting it is at 
http://cert.peak.org/"

	The site cert.peak.org has the heading "Certificate Authority Update"
and a section "Download CAcert.org Root Certificates for your browser
with entries for "most browsers", "Internet Explorer on Mac OS X", and
"Internet Explorer on Mac OS 8.1".  The only one seeming at all relevant
to evolution was "most browsers".  So I've downloaded a text file
containing some sort of encrypted gibberish with -----BEGIN
CERTIFICATE----- at the top and -----END CERTIFICATE----- at the bottom.

	Will this work with evolution?  If so, how do I install it?  The
program documentation is sketchy, to put it mildly.