[Gtk-sharp-list] TreeViewColumn alignment

[Benoy George]

Dear Friends,

Please help me on how to right align a column in 
Gtk.TreeViewColumn

My current column definitions are

	col = new TreeViewColumn ();
	colr = new CellRendererText ();
	col.Title = "Expense";
	col.PackStart (colr, true);
	col.AddAttribute (colr, "text", 2);
	col.Alignment = 0.0f;
	col.Resizable = true;
	tv.AppendColumn (col);

I want to align above said column Expense to right-align 
with two decimal point. I googled a lot, but no way to get 
it done.

Sincere thanks
Benoy