[Sketchup C API] Set mm as units of newly created model?

[rahulnejanawar]

I see that there is a way to get units SUModelGetUnits from the model. But no method to Set the units for the model/file.

So, is it possible to set the units?
If yes, what is the method or is there any other indirect way - such that the new file gets saved with "Millimeters" units?

Note:This question has been posted earlier as part of this thread http://sketchucation.com/forums/viewtopic.php?f=180%26amp;t=57909.
Since this is a different question from the original thread I have added it separately.