Sure you can use a DNS Hostname like DynDns for example ... I think this one is not free anymore but there are others that are still free ... Then instead of indicating your public IP (the one that changes every x hours), you indicate the DNS name into Enigma-TV. You will have to setup this DNS into your router, all routers have this function ... just check how it works on yours. (very easy)
Thanks for the enigma-tv program,it is working fine here! One little problem: I've a dynamic ip-address (changes every 24h) and enigma-tv doesn't automatically update the external ip-address and then i can't stream, i get an error. Can you automaticcaly update the ip-address at the start of every stream request?