Create Interface for Elastic IP for VPN

Question

Hi, 
 I launched a Cloud Formation (cold HA) of Sophos UTM9 and now would like to connect it to a VPN. 
 I am stuck at selecting a public network interface for the VPN. The Cloud Formation only created a private interface for the local network. 
 How would I go about creating this public interface for an elastic IP? What kind of Interface Type would be the correct one? 
 The machine is already accessible over the elastic IP (via :4444 and :22). 
 
 Disclaimer: I am very new to the world of networking.

Marius Stefan Bethge · Answer

I found the solution to my issue. 
 Following: https://community.sophos.com/products/unified-threat-management/f/vpn-site-to-site-and-remote-access/74478/please-some-way-to-override-the-ipsec-conf-left-x-x-x-x-setting 
 I went ahead and set my VPN ID to my Elastic IP, which lead to the IPsec tunnel using the Elastic IP and thereby agreeing with remote gateway on the left VPN ID.