An A320 Captain diverted from SFO to SJC because SFO only had Runway 10 GPS and VOR approaches and Company policy did not allow flight crews of non GPS aircraft without line selectable FMGC VOR approaches to manually build VOR approaches.

Narrative

I was the pilot flying; Captain pilot not flying. Inbound after I reviewed the FM Maneuvers section for Non-precision approaches due to using Runway 10L RNAV (GPS) or VOR-B. If we had been allowed to build the VOR approach manually we could have gotten in easily and not had to divert. Ceiling was 2400'. Since we did not have GPS we could not do the RNAV. Since we did not have the VOR-B as a line selectable approach we could not do that per the FM Managed/Selected requirements. It specifically states that a VOR approach MUST be LINE SELECTABLE. Why do we have a chart for this IAP if is not in our database. It is a source for definite confusion if you don't know the limits very well. We asked approach to vector us at the MVA for a visual. The MVA was 2600 feet and the previous aircraft were breaking out below 2400 FT. ATC said they could not vector us that low west of SFO. They recommended SJC vs. OAK and would not vector us at the MVA. After a short divert discussion between us we elected to go to SJC. We sent limited information to dispatch regarding our divert to SJC. We landed in SJC uneventfully and then flew back to SFO after being serviced. We did not deviate from any policy; procedure; or FAR. I believe this is a potential safety issue that should be addressed.