You will need to port forward and AFAIK NAT is the only option (although perhaps others will prove me wrong).
When you say NAT didn't work, I'm assuming you used VirtualBox's builtin NAT using instructions such as these or these?
I suggest you have a look at the official VirtualBox NAT documentation. If you still cannot get it working, I would suggest posting on the VirtualBox forums. And if all else fails, log a bug on the VirtualBox bugtracker.
Port Forward!
You will need to port forward and AFAIK NAT is the only option (although perhaps others will prove me wrong).
When you say NAT didn't work, I'm assuming you used VirtualBox's builtin NAT using instructions such as these or these?
I suggest you have a look at the official VirtualBox NAT documentation. If you still cannot get it working, I would suggest posting on the VirtualBox forums. And if all else fails, log a bug on the VirtualBox bugtracker.
Good luck!