adding a disk to unix system.

Hello everybody,

I am traying to add a new external hard disk (300 GB Seagate ST3300007LW)
to our Ultra-I SUN Workstation running Solaris 2.6 operating system.
System recognizes the hard disk on target id=13, and I am able to reboot
with the command "boot -r". However the "format" command does not
reply correctly, do not list the already attached hard drives and this new
one. Please, advise how to proceed... best regards.