MTX8000 is a privacy plus trunking radio, type I, II and IIi. It will not do SmartNet, which is an fits the APCO16 standard with options such as dynamic regroup. Needless to say any MTX8000 (except the B3 model) will program a typeII trunking system, but the radio itself is not compliant and will not follow dynamic regroup commands (and there are others than just that one, but I can't think of it). Furthermore, not being Public Safety radios, they do not program in the 866-868 section of the 800Mhz band, they're not type accepted for it.
City of SanDiego is either using MTS2000 radios (which look the same, but are public safety radios) or they're using MTX8000 radios on the system, which by itself if fine (assuming sandiego's frequencies are within 851-866Mhz), but I hope it's not public safety using it, but rather city-services or something. If Public Safety (PD/FD) is using MTX8000s for SmartNet/SmartZone type applications, someone made an error ordering radios because they are not public safety equipment, nor were they ever marketed as such.... that's why there's the MTS2000.
Now, as far as programming 866-868 NPSPAC frequencies into the MTX8000, I'm sure there's a hex-edit that will do it. You could also use lab to force an MTS2000 codeplug into it, however, since the radio's firmware doesn't support the public safety APCO-16 features associated with SmartNet trunking, the best it would do is allow the additional frequencies to be programmed.
-Josh