ListGrid Checkbox Header Controls?

With an explicit ListGridField, I can set a header icon by ListGridField.setIcon("MyImage.png");

Is it possible to achieve a similar result for the implicit column generated by ListGrid.setSelectionAppearance(SelectionAppearanc e.CHECKBOX); ?

How can I access the selection checkbox column header?

Even though the Grid will allow multiple selection, I do not want a "Select All" checkbox in the column header. Instead, I want a replacement image with no functionality.