NatTable natTable = new NatTable(parent, NatTable.DEFAULT_STYLE_OPTIONS | SWT.BORDER,
                gridLayer,
                false);

public class NatTableSelectionBindings extends DefaultSelectionBindings
{

protected void configureMoveUpBindings(UiBindingRegistry uiBindingRegistry, IKeyAction action) {
	super.configureMoveUpBindings(uiBindingRegistry, action);
	uiBindingRegistry.unregisterKeyBinding(new KeyEventMatcher(SWT.SHIFT, SWT.CR));
	uiBindingRegistry.unregisterKeyBinding(new KeyEventMatcher(SWT.SHIFT | SWT.CONTROL, SWT.CR));
}

protected void configureMoveDownBindings(UiBindingRegistry uiBindingRegistry, IKeyAction action) {
 // same as above
 ...
}

}

        natTable.addConfiguration(new MyNatTableSelectionBindings());
        natTable.configure();