Q: Can I manually open the ports for Back to My Mac on my 3rd party router's firewall?

I have AT&T U-verse and it's RG (Residential Gateway) does not support NAT-PMP or UPnP, I suspect because the IPTV uses it. I found this article that specifies the ports that Back to My Mac uses:

TCP and UDP ports used by Apple software products - Apple Support

Is it possible to manually open these ports on my U-verse for my Mac? Or does Back to My Mac have to use NAT-PMP and UPnP?