You need to set the viewpoint after assigning the manipulator to the viewer (and after assigning the viewer's scene data as well). I have never tried setting a viewpoint before starting the viewer's frame loop; maybe it will work, but if not, call setViewpoint after starting the viewer (using an eventhandler or an update callback or something - see osgearth_simple).
Regarding your viewpoint: The focal point it x,y,z; so you probably want to swap your lat and long (since lat is y and long is x). You also have a pitch of 0, which means your camera is parallel to the ground; -90 would be straight down for example.
Thanks! And, it looks like setting the viewpoint before the frame loop does not work (not really a problem). Thanks for the viewpoint tip, we have 1 interface that does (lat, long, alt) and another that does (long, lat, alt) so I'm always mixing them up. Everything looks good now, thanks.