The SMG works at the SMTP level with your mail server, therefore the version of the mail server (whether that be Exchange, Domino, MDaemon) doesn't really matter for the flow of mail. The SMG will work fine with Exchange 2013.
Win2k8R2 can be used as an LDAP source for the SMG from v9 and up (including v10 that you're running):
http://www.symantec.com/docs/TECH97476
http://www.symantec.com/docs/HOWTO53676
I'm afraid I've not been able to locate a full compatibility matrix, but yo might have better luck rummaging around the SMG KB:
http://www.symantec.com/business/support/index?page=landing&key=53991