I don't think this is possible. You could use an enumeration (e.g. yes/no/empty) and add a small .png image with a checked checkbox for 'yes' and an unchecked checkbox for 'no'. Based on the boolian you can set this enumeration's value. Within a grid its possible to show an image when you use an enum within a column of the grid. A dirty trick, but it'll give you what you need I guess. Hope that helps.