QTableWidget Cell line width control to create borders on top,bottom,left or right

Hi,

I'm trying to develop an application to generate latex tables graphicaly. Until now i got this features:

-Span Cells;
-Clear all spanned cells ( i want to clear the span in just one at time instead);

But now i really need to be able to modify the borders of the QTableWidget cells in order to the user be able to select where the lines will be in the table.

I searched a lot in the API's and trying to get over it using Styles and Brushed but without sucess.

Can someone help with this?
Cause i'm completly stuck :s

Sorry for my english. I want to do is to change the line style in a particular cell. I built the QTableWidget with dashline grid style and now i want to set normal line for a particular cell , including control of of lines in the rop,bottom,left and right for that cell.