Hello Jozef,

I just got thru doing something like this with a similar setup: 
we use Emulex LP8000 cards for the HBA's onto an IBM 3584 with LTO drives
and a Mcdata switch. There are 4 things that need to be done or it won't
work:
0. Ensure that you've moved the /kernel/drv/st.conf somewhere else. Solaris
will try and grab your scsi tape devices otherwise.
1. Make sure your fabric is set up correctly and that at boot up
(ck the /var/adm/messages files) you see your IBMtape device drivers and
HBA acquired targets. Here's a clip of what I'm talking about:

May  3 18:04:35 bst7-1 unix: IBMtape254 at lpfc1:
May  3 18:04:35 bst7-1 unix: IBMtape178 at lpfc1:
May  3 18:04:35 bst7-1 unix: NOTICE: lpfc1: Acquired FCP/SCSI Target 9 LUN 1
May  3 18:04:35 bst7-1 unix: NOTICE: lpfc1: Acquired FCP/SCSI Target 9 LUN 2
May  3 18:04:35 bst7-1 unix: NOTICE: lpfc1: Acquired FCP/SCSI Target 9 LUN 3

3. Next check that your /usr/kernel/drv/IBMtape.conf file has the requisite
objects not #'d out. We typically leave all 16 instances open.

Bern Ruelas
Sr. Systems Engineer - Storage
Cadence Design Systems