Problems with component IUCONFIG (Product config) view Configtree, please

When I create an enhancement for component IUCONFIG, this enhance let me generate GET_I* , GET_M, GET_V and GET_P* in node ISUORDERITEM, but in node ISUORDERITEMCONFIG doesn't let me redefine this methods GET_I, GET_M, GET_V, GET_P.

I would like to get one of the possible values of a dropdown listbox with the methods GET_I, GET_M, GET_V, GET_P. Is this possible??

Why can't I redefine this methods in node ISUORDERITEMCONFIG ???

Thanks in advance.

Regards