Curtain wall edit question

[Conrado Dominguez]

Using the curtain wall for storefront(s) infill is a good tool to use.

Using a floor plan as a trace reference, I can see exactly where I need to place the mullions to meet interior walls or other desired location.

Editing in 3Dmode is not good because I loose the floor plan reference; editing in elevations renders the correct image but only in the elevation view, not the model.

I would like to know of there is a way to edit(move) the mullions location with the curtain wall shown in the floor plan view.
The logical tool I can think off is using the marquee tool and stretch command, but that does not work either.

Your help will be appreciated.