one additional information:
If I export my certificate from the eToken (either via the Aladdin eToken properties or the native Mac OS X Keychain Access), import it manually into the Cisco VPN client and try to setup the VPN connection, the "Certificate Authentication" select box on the "Authentication" tab remains empty (i.e. the certificate imported earlier does not show up here nor in the "Certificates" tab).
(On my Windows XP, the certificate automagically is selected in the "Certificate Authentication" select box (and appears in the "Certificate" tab) as soon as the eToken is plugged in)
Maybe this helps in helping me :)