CTreeCtrl state image limited to 15 images

I have a CTreeCtrl that uses "state images" to get a second icon next to the normal icon. From the documentation here http://msdn.microsoft.com/en-us/library/fc4e6etb(v=vs.80).aspx:

If a state image list is specified, a tree control reserves space to the left of each item's icon for a state image. An application can use state images, such as checked and cleared check boxes, to indicate application-defined item states. A nonzero value in bits 12 through 15 specifies the one-based index of a state image (0 indicates no state image).

Since there are 开发者_Go百科only 4 bits and 0 is reserved to indicate no state image, you can only have 15 state images. This is mentioned here as well: http://www.codeguru.com/cpp/controls/treeview/usingimages/article.php/c669

Question I've used up all 15 state icons and would like to add more. What are my options to achieve this?

Implement a custom-drawn tree-view or find such an implementation.