AutoCAD Inventor :: Converting Step Files For Mechanical Desktop?

I have a problem with some step files I recieved from a vendor for an assembly.  Basically what is happening is I download the step file. Then bring it into Mechanical Desktop.  When brought into Mechanical desktop, it is downloaded in metric where my entire assembly is in standard/english format.  What I did when I had Inventor 2011 is bring the step file into inventor, go to document settings and switch the unit to inch from mm.  Then save the step file and when I brought it into Mechanical desktop it was in the correct unit and scale.

Now with 2012 Inventor, when I bring the step file in, it is automatically in english/standard format.  So I save the step file out and try to open it in Mechanical desktop only to have the file back into mm and 25.4x the actual size it should be.

how to save the step file out like in 2011 to make sure the unit is saved in the correct format.  This is extremely aggrevating and waste of time.  I would have had the part reverse engineered by now if i quit trying to use the vendors standard step files.

This problem doesn't only happen with a certain vendor's drawings either, it goes for all step files I have recieved since getting Inventor2012.