[NTG-context] Thickness of right border for table cell

In order to change the width of the bottom border of the first row of a natural table to 2bp, I can do \setupTABLE[row][1][after={\hrule width\hsize height 2bp}] and I have tried doing \setupTABLE[column][1][after={\vrule height\vsize width 2bp}] to change the width of the right border of the first column, but this does not work. I would appreciate some expertise on this. Thanks, Troy Henderson