DataGrid - Alignment when using custom DataGridTextBoxColumn styl

[Randall Cornish]

I have implemented the DataGridTextBoxColumn code that allows a particular cell to have custom formatting (DataGrid FAQ 5.67). This code was straight-forward and I had no trouble making it do what I wanted - bold the last row in the grid. However, when implementing this code, I seem to have lost the ability to influence the Horizontal alignment at the Column level.
if (j == 1 || j == 2)
{
cs.Alignment = HorizontalAlignment.Center;
cs.Width = 100;
}
Both examples I have seen on this Paint() event handler seem to also have ALL the cells left-aligned. Do I now need to implement another event handler to get my alignment ability back?

Thanks,