@OK465, i don't know if its about the coding or the FMS. However in the companies i've flown the 737 and in the short time i'm on it (just 11 years now) we always had a coded descent path that was on the legs page. However i cannot remember a single approach we use where the missed approach point is behind the runway.
That said, VNAV is only a backup mode nowadays, IAN is the primary mode and that one works like an ILS. The MCP speed window is open and the approach mode follows the FMC generated final approach course and glide path (FMA modes FAC and GP).