Arch Model into MEP results in missing elements

[MooksBK]

When I import the Architect's Revit 2010 model into Revit MEP 2010, the roof elements all disappear.

I have checked all the usual settings, view disciplines, worksets, and it appears and though nothing is hidden. Every other part of the model comes in fine, just all the elements associated with the roof across several levels are neglected. Can anyone help shed some light on why this is occurring? Perhaps there is some setting that I am missing here?

[Scott Womack]

It is possible that these items were created on a workset that is Off by default in the Architectural model, or are in a design option, that is not the primary option.

I don't know why they'd use a workset that is off by default, but it is possible