file-upload control in grid?

I need to embed a file-upload control into a grid. I tried

var uld=new AW.UI.Input;
uld.setAttribute("type", "file");

It won't work. It only showed up as a text box without browse button.

Then I tried

var uld = new AW.HTML.INPUT;
uld.setAttribute("type", "file");

It works for standalone. However, if I try to embed to a grid by

grid.setCellTemplate(uld,0,0);

It won't work. It seems AW grid can't embed any AW.HTML object as template.

Is there any solution?

Thanks,