In that case I would try to configure the Magento URL to your domain, chain the port forwarding rules, you will need to forward from your real host IP instead of
127.0.0.1 (I mean, a non-loopback IP).
Then point your domain to your host IP.
You will lost the connection using
127.0.0.1 but you should be able to access it using the domain.
Let us know what happens.