S/MIME Certificate renewal in W2K3 - EX2K3 infrastructure

Hi all,

I've implemented secure messaging as described here:

http://www.msexchange.org/tutorials/Email_...hange_2003.html

In my GPO I configured Autoenrollment and checked the two boxex "Renew

expired certificates..." and "Update certificates..."

The renewal period in my template is 6 weeks and the certificate expires

after one year.

Now I'm wondering why it is necessary to keep the old certificate in my

certificate store after getting a new one within the renewal period. If I

remove the old one I am not able to decrypt mails being encrypted by using my

old public key.

I thought the private key remains the same if the certificate is renewed and

I would be able to decrypt mails that are encrypted with both public keys -

the old and the new one.

Can anyone arrange my ideas? :-)

Thanks a lot

Andy