After reviewing the Mann-Hummel unit documentation, what appears to be a vacuum regulator on the side of the unit is actually a positive pressure blow off regulator.
If you're not going to use a low vacuum, closed regulation system like the stock BMW CCV unit, then I believe that the only safe alternative is just a vented catch can. I believing connecting full manifold vacuum to a closed crankcase is a bad idea. I'll be posting a bunch of technical information on the CCV subject in the near future.
"I'm a little rascal on my Little Rascal"