[gtkmm] listview: setting textcolor in individual cells in the same column

[bart <bart hakvoort castel nl>]

Hello,

Thanks to some help from Christer and Murray i'm now able to modify the
textcolor in a column. This is great, but now i need to set different
colors in different cells in the same column. I don't know how to
achieve this, i don't know if this is even possible!
Mabe someone here could give me a hand.
This is the code i use to color everything in column "naamkolom"
darkgreen.
===========================================================================
Gtk::TreeViewColumn* naamkolom = get_column(1);
Gtk::CellRenderer* cell_renderer = naamkolom->get_first_cell_renderer();
Gtk::CellRendererText* cell_renderer_text;
cell_renderer_text =
dynamic_cast<Gtk::CellRendererText*>(cell_renderer);
cell_renderer_text->property_foreground() = "darkgreen";
==========================================================================

Problem is, some cells should be red instead of darkgreen. And if i
change them everything turns red. 

grtz,
Bart