Matrix column as a LinkedObject

Hello everyone,

I'm trying to set my Matrix Column Type as a LinkedObject. I know how to do that via the ScreenPainter, but i must do it via code for it is changeable.

oColumn.Type = SAPbouiCOM.BoFormItemTypes.it_LINKED_BUTTON;
oColumn.ExtendedObject = "23";

after using that code, i see that both Type and ExtendedObject properties are read only. if so, how can i assign these values?