I had the same issue with ISE v2.1 setup: Here is the solution found in installation guide: • Cisco ISE is a 64-bit system. Before you install a 64-bit system, ensure that Virtualization Technology (VT) is enabled on the ESXi server. You must also en...

Hi there, The below URL may assist you (it discribes ASA-to-ASA L-2-L VPN using PKI): http://itzecurity.blogspot.com.eg/2014/02/cisco-asa-ikev2-pki-site-site-vpn.html  If you have already sorted it out, please share your resolution.