I upgraded the MacMini to OSX LION 10.7.2 and suddenly found that no audio was coming out of the BV8.
I went down a number of wrong paths (cable borken, reset microcode, HDMI cable not matching HDMI 1.4 support, etc) before discovering it was a "feechure" that Apple introduced:
Apparently this change was intentional in 10.7.2 to bring the behaviour of the headphone jack in line with the experience of users who have external displays connected via Thunderbolt !
I've replied to this advice by pointing out that this change actually removes functionality that was present in 10.7.0 / 10.7.1 and requested that the issue is esculated back to engineering for further comment..
I'll post again when I recieve the next reply.