ezjail and ports

[Dave]

Hello,
    I've created three jails with ezjail on a 6.1 machine. When i did so i 
did not need ports, now i do in one of the jails. I've tried nullfs mounting 
the host system's /usr/ports tree, but it didn't automount on jail startup. 
So, i fetched a new copy of the ports tree in to /var/ports, but when i 
tried to install a port, bash3 in this case, the ports are referencing 
/usr/ports/share/MK which it can not find,     that's a read-only symlink to 
the basejail filesystem.
    A side question, pinging the jail works fine from the host system, but 
nmapping it does not show anything even though i have running services. I've 
tried with and without the -P0 option.
Does anyone have this working?
Thanks.
Dave.