[Gtk-sharp-list] removing childrens of a node in treeview

[Rampage]

Hello everyone :)

right now i'm using a sort of dirty trick to be able to run a 
testexpandrow method in my treeview.
i add a dummy value so that i can test the expansion and trigger a 
method that populates with real values.

the problem is that i want to remove that value once the real children 
have been added.

can anyone point me in the right direction with some docs?
couse i browsed the api documentation and searched for examples but 
nothing around :(

thank you very much.