Problem when adding Form Controls to Excel file using OpenXML C#.

Question

Hi,
I am using Open XML SDK in one of the projects I am working on to create Excel file that would need to have Check boxes(Form Controls not ActiveX controls) in some of the cells. The problem I have is that no matter what I try for adding those controls it simply doesn't work. I even tried getting the code from Open XML productivity tool to see how they are added but that also didn't work. So I was wondering if it is even possible to add Controls to excel file using Open XML and if it is could you help me with code or documentation on how to do it.
Thanks in advance.