That’s because the package manager UI shows only packages from repositories listed inside /etc/nethserver/pkginfo.conf.
The reason is to prevent the installation of unsupported packages on machines with a subscription.
So to overcame the limitation (this will be lost on next cron run):
echo nethforge >> /etc/nethserver/pkginfo.conf
yum clean all
yum updateinfo
The second one: the support team will always tries to do his best! I know this is one of the most appreciated things from our customers 
Still there are some scenarios where is hard to give support, like when running docker on a machine which is also acting as a gateway for the network.