I have done this LOC approach, EFIS LNAV a/c. Self positioning FMC approaches were not allowed by SOP's. However, I asked ATC radar to confirm us crossing EDEMO (radar fix). I maintained 3300', which gives a 3 degree path from EDEMO. This was now my TOD, NOT TRE; that's too close. Set up a V/S, re: Gnd Spd, to give 3 degrees and made sure we didn't bust the FAF 1900'. F5. Configured Gear down etc. passing 2000' and confirmed crossing TRE >1900'. All simple and legal, but only with the radar fix. This type of approach is often standard in Scandanavia. If you have a GPS a/c use of the green arc is invaluable. Diving to 1900' can only be done with ATC confirming EDEMO anyway, but it makes it all very rushed if TRE is used as TOD from level flight.