The SmartThings Z-wave implementation is broken at the moment.
Device handlers can send AssociationGroupingsGet() messages, which the handlers use to determine how many buttons are to be set up, but the SmartThings platform is not providing the AssociationGroupingsReport() to the handler.
Sniffing the Z-wave network I can see the packets arriving at the VRCS4, and I can see it responding to the correct address of the hub. The SmartThings Hub is then not propagating the message up to the device handler. It is not fully broken because I can see where a ManufacturerSpecificReport() is being received from VRCS4 upon request.
There may be a hack around this; the handler could send association and scene configuration based on an assumption about the devices characteristics.
FWIW my hub is on firmware 000.027.00009.
Until SmartThings fixes the above issue, no handler that configures itself via this API is going to work.