GtkCellLayout::set_cell_data_func issue in Gtk2

I just upgraded from the Beta to php-gtk 2. I've been tweaking things to work with it (mainly the Gtk::TYPE's to GObject::TYPE) but I've run across one issue with GtkCellLayout::set_cell_data_func. Before, I could pass it a callback function in the current class like so: $col->set_cell_data_func($renderer, array($this, 'format_col')); And that worked fine.. now it seems it won't take the array and returns an error: Warning: Unable to invoke callback 'Array' specified in File.php on line xxx Has this changed any in the new release? Thanks! -Matt