How to use tiny pointer with boost::intrusive::rbtree?

[JaydenFish]

I need a custom boost::intrusive::rbtree whose node_ptr is uint32_t. All nodes are allocated from a array. So its node_ptr(pointer to left child, right child and parent) can be uint32_t but not void *. uint32_t is index of the array. So I can optimize memory use. How to do? Thanks very much.