cell event

I am trying to create a table with cells that have a dotted line for a border. How can I do this?
I have to create a table having rounded corners, something like it: Cell with rounded border Can I do it with iTextSharp?
When I try to create a dotted cell I am using a PdfPCellEvent . However I get all of the borders drawn with dotted line. When I set up the cell.setBorder(Rectangle.BOTTOM | Rectangle.RIGHT); the bottom and right get drawn with solid line. When I remove the setBorder() I get all borders dotted.