Hellow,
There are no need of BMR in recovering boot disk from tapes.
What you need is described in Troubleshooting Guide. Check the section like "Recovering a Root Disk and Root Mirror from Backup Tape".
VERITAS Volume Manager (tm) 4.1 Troubleshooting Guide for Solaris
http://support.veritas.com/docs/275762
VERITAS Volume Manager (tm) 4.0 Troubleshooting Guide for Solaris.
http://support.veritas.com/docs/265473
VERITAS Volume Manager 3.5 Troubleshooting Guide (Solaris)
http://support.veritas.com/docs/248611