You can achieve the setup thru configuring ipsec vpn client. For the users in your inside lan to access server 1 in DMZ1, you just need nat / pat and make sure to permit the traffic if you have ACLs configured. If it's possible to upload your current config with the servers' ip then I could help further with details.
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...