[squid-users] Reverse and SSL cert

After little problem I installed squid 3.1.1 with openssl on my ubuntu
server 9.10.

Now i have my ssl certificate (.cer) on my exchange server but squid (or
openssl ?) require a .pem certificate.

I have doubts about this.

Is the certificate the same of exchange ?
(if yes) The same certificate will installed on squid and on exchange?
How to make the .pem certificate for squid?

thanks

-- 
Andrea Gallazzi
http://andreagx.blogspot.com