What you'll probably have to do is to work out a lookup table for the various ways of displaying a given character. Since you'll probably be limited to 0..9 and perhaps A..F, the table won't be too large. The "easy" way to do this is to get some sort of cathode driver, such as what Erik suggested, but you might want to look up DS- or DM-8650 in a National Semiconductor databook of pre-1990, or maybe even pre-1980 vintage. ISTR that they made something with those numbers. Aside from that, it looks to me as though you're on your own. This thing may, in any case, be pretty old.

RE