Centering text in a cell

[Chris Manning <cascadia swiftdsl com au>]

Hello again,
Does anyone know how to center-align some text in a cell renderer? 

In my function where I'm rendering my cells, I have this:
gtk_tree_view_column_add_attribute ( column, cell_txt, "text", 1 );

And in a callback function I have this:
gtk_list_store_set (GTK_LIST_STORE (store), &iter, 0, my_text, -1);

This works in that it adds my_text to the cell. However, this always
results in the text being left-aligned and I need it to be
center-aligned.

Any help much appreciated!

Chris.