Hey folks,
I have the AF-3500 (non-S) with the Tru-Trak DFII VSGV, ARINC adapter and did an AP coupled GPS LPV approach a few nights ago.
The procedure was as follows:
GNS-430W: loaded and activated the approach enroute as is normal in the GNS 430W
Enroute: EFIS Lat NAV, Vert ARM
Tru-TraK: GPSS, ALT enroute, descended and leveled off at the IAF using the ALT function of the AP
Then, when on the final approach course, outside the FAF, selected GPSV on the Tru-Trak
Vert ARM went to Vert NAV (although I don't recall if this was prior to enabling GPSV or when I intercepted the final approach course)
I'll do a coupled ILS approach within a few days and observe any differences in an ILS versus LPV;