@ohosh
On this site: you don't. It is not implemented as far as I know. BUt it is on Russ' to do list for a long time.
Otherwise by moving the King tweo steps in direction of the rook and moving the rook to the filed next to the King
@Ponderable
It really has been way too long. The big re-engineering of core RHP to support this properly is 2 minor app updates and 1 server migration away!
(In other words, I'm preparing for it now...when it will be released though, I can't be sure.)