OCAF functionmechanism

Hello,

i have problems to get the functionmechanism to Work. Imagine the following ocaf tree structure:

main
--- top label 1
--- top label 2 //depends on geometrie childlabel
--- ref 1
--- ref 2
--- geometrie //depends on ref 1 and ref 2

I have working TFunction_Driver's attached to all labels (exept main), but by doing:

TDocStd_Document::Get(ref 1)->SetModified( ref 1);
TFunction_Iterator iter( top label 2);

no functionlists are available by the iterator (iter.More() returns false). What am i missing in the function initilaising? I've read the ocaf_functionmechanism and it seems this is the way to go.

Any help would be appreciated.

Thanks,
Stefan