iorchid - all I know about this species is that it comes from Borneo and grows in low altitude moss forrests. So considering that I would guess that it would be grown shaded and probably doesn't ever want to completely dry out. If it were me I would give it the same culture as Phals. Good luck !
"moss forests on rocks and boulders"? sounds more like a lithophyte than a true terrestrial; IOSPE is awesome, but it does have some confusing descriptions. Some phals from Borneo grow on rocks, as well; say, Phal cochlearis. So I'm guessing Phal cochlearis conditions may work. It's just a guess though, so I may be dead wrong on this one.