record 5.1 surround AC3

99% of time when we are editing with FCP 7 clients send us AC3 or six separate Aiffs for the 5.1 surround.
However ... this time we need to record the 5.1 surround from a DVD as the hard disk they created the DVD and the original FCP project has crashed ( I know will people never learn to backup) So ... we used to use a little FIREWAVE to decode the Dolby or DTS 5.1 into FCP7 but ... it won't work with Lion or Mountain Lion.

We use multiple Black Magic Declink Eclipses so on the back the only input really are AES/ EBU XLR which we can take 6 channels in. So it may be buy new kit time.

I don't care if i buy a USB, Firewire, SATa , Thunderbolt connected decoder ... we just want to feed the optical cable into " something" so it can decode the AC3 and then i can record it into FCP7 as 6 separate tracks. Bought 3 or 4 "gadgets" all claiming to connect via USB and then convert the optical dolby 5.1 so we could record but everyone of them converted to just 2 channels

Now to add spice ... the MacPros we use all have optical (light pipe ) IN AND OUT. We faffed about for hours with terminal with AC3 passthroughs etc but no luck.
I can happily PLAY 5.1 surround from the mac but we want to RECORD the 6 channels of audio (left, right, centre, sub, surround left, surround right) into FCP so we can edit etc.

Can anybody help. Obviously prefer pro equipment but if it means cobbling 2 or 3 domestic convertors together .. so be it.

I know ... I know if only the muppets hadn't ruined the hard drive they made the master from ... then it would all be done by now.
We have VIP account with Apple and yet ... they are all scratching their head on this one.

Anybody know hardware or software we can go
from optical 5.1 Dolby or DTS to FCP 7
or ....
from Optical 5.1 dolby to DB 25 connector so we can use this
www.avid.com/US/products/DB25-XLR-M-F-AES-EBU-DigiSnake12

RECORD 5.1 optical as 6 separate tracks in FCP7 ? can anybody help please
kind regards
johnny B