Move Certificates from Server to Remote Computer (MACS)
scp provides a handy way to do this. It also happens to be nearly platform-independent (Windows requires Cygwin or similar). 

Ex: from the Mac you want the certs on:

scp -r user@server:/path/to/cert/directory /where/you/want/the/certs


Note that the '-r' option works on entire directories, if you only want to work on the certs, not the directory containing them, you may ignore it.