GNode and GtkCTree

[Randy Rueckner <unicorn minet uni-jena de>]

hello there!

i write a little application to manipulate and filter magnetic resonance
tomographie - images using glib/gtk.
the main part is done - gtk is really great, but now i have a little
problem and hope someone here can help me.
i want to build a GtkCTree which shows the local images, but that is no
easy task.
the images are named as follows: xxxx-yyy-zzz.ima, where xxxx, yyy, zzz
are integers (xxxx ist the patient id, yyy the study no and zzz the image
no in the study yyy).
the GtkCTree should look like this:

---local IMA's         // the root_item
 |-+-3331              // patient_id = 3331
 |-+-4222
 |---4546
 | |-+-2               // study_no = 2 ( for patient_id = 4546)
 | |-+-3
 | |---6
 | | |-23              // image_no = 23 (in study_no = 6)
 | | |-24              // filename for this entry: 4546-6-24.ima
 | | |-25
 | | |-84
 | |-+-8               // study_no = 8
 |-+-5123              // this is the next patient_id
 |-+-5423

i hope you understand what i mean.
so i read all image names into an array, split them and build an GNode
tree. my GNode - tree is correct.
now i tried to add my GNode_root_item into an empty GtkCTree.
but in my application there is only an empty item shown, like this:

-+-

and nothing more...
i can click on plus, but without an effect. where is the rest of my tree.
please help me.

thanks in advance
randy