To be specific the 445 only supports solaris 9 9/05 HW aka solaris 9 9/06.
Or solaris 10 6/06 aka solaris 10u2.
Both of those OS versions were only just released just as the 445 hardware was just released.
Why would you expect an OS released about 5 years ago to support just released hardware?
Solaris 8 on the V445 platform ?
... not going to happen.
Here's a recent discussion from the Hardware Forum.
http://forum.sun.com/jive/thread.jspa?threadID=108466
(Recent = only four weeks ago)
In particular, see the 11-Oct-06 response in that thread, from contributor Maalatft.