I am running 2014 and still having the issues described in the OP. Are there any setting to envoke or should this be fixed out of the box?
This issue has been resolved in AutoCAD MEP 2014! Out of the box it does not work.... I had to set HIDEPRECISION to 1 and check "Save Hidden Lines in Drawing" under MEP Display Control tab in OPTIONS.
These changes also make the drawings generate much faster when opening drawings or changing between model and paper space. Good job Autodesk! Many thanks to Joshua Benoist for following through on this request!