OWA 2010 - Reverse Proxy -- continue

["Andrea Gallazzi" <andrea.gallazzi@xxxxxxxx>]

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