Help with eclipse plugin

I need some help with WebOnSwing "plugin" for eclipse. The idea is create an extension to VEP (visual editor of eclipse project) to manage one more LayoutManager that is request by WebOnSwing. This LayoutManager, called TemplateLayout, is like BorderLayout but more generic; it means that should manage contrainsts like "NORTH, WEST, EAST, SOUTH" and any placeholder like this in arbitrary coordinated positions.