igreere,
Im not sure i understand your question completely but...
If i am reading your question correctly, the problem probably lies with the setout of your scheme. If you select the curtain wall in 3d and then edit, then turn off all except the scheme you will be able to see where your curtain walls setout point is. You can then use the pet pallette to move the scheme up and down to get the setout point to the base of your curtain wall boundary.
After this, adding any more rows in the Number 1 position will appear in your model.
Hope this helps and have answered your question.