can you be more specific about exactly what wouldn't work? I'd expect fluid flow to be as per a standard convertor when past 'stall' speed, and the 722.xxx series transmissions have a rear pump anyway, so seals/lubrication/fluid flow aren't an issue. Automatic control isn't a factor either - as I'm more interested in synching it with the compression brake for my application, it can be as simple as a contact switch in the lever that controls airflow to the jake. (its a 240D, BTW, and has already had a custom turbocharger added)
Perhaps you'd care to describe exactly how the MB lockup convertor is different to the standard convertor - I understood that while they potentially had different dimensions, the lockup convertor was essentially teh same unit with an electrically actuated clutch inside...