...Nothing about PAPI/VASI...
I quite strongly disagree. The various references to "stabilized approaches" including the link posted earlier
http://flightsafety.org/files/alar_b...blizedappr.pdf all list the number 1 criteria as "The aircraft is on the correct flight path"
Flight path is always defined as both Horizontal and Vertical. Maintaining a VASi, in the absence of an accurate ILS system, would certainly fit the requirements of "...correct flight path..."