Hi Ben
In Sibelius 6 go to House Style > Edit Instruments > - VDL Template 7.0a > World Percussion (or a different Family) > select an instrument, click Edit Instrument, then click Edit Staff Type. From the Percussion tab, scroll over to what matches EXACTLY as what the Maps diagram shows, select it, then modify/delete. OK, OK, Close, save file. I've attached an image that may help.