Restore old tapes from BE 12.5 using NBU 7.5 and beyond

We currently have a Windows Server 2008 R2 hosting a NetBackup 7.5 media server.

we have old BE 12.5 tapes that we need to have access to for future restores.

We found BETR will be discontinued with NBU 8.x. Also BETR does not support BE versions higher than 12.x per TECH125836

we also found that BE 12.5 is not supported on our new Windows Server 2008 R2 - per TECH62301

What is the recommended best practice for mantaining accessability to these old BE tapes now that we are primarily a NetBackup envirenment?