I built my kit to do TTL-serial only, and I don't plan to use real RS-232 voltage levels.? So I have a FJN3403 and a FJN4303 new in the package here.
If you want them, contact me offline at frank@... and I will send them to you.
For an active part, it seems like you could find a match in a surface mount package, if you're willing to solder that to the top (or bottom, depending on the pinout).
I think a SOT-23 can fit on TO-92 pads?
Another alternative would be to find a compatible?N-channel and P-channel FET in a TO-92 package, which would be ok with the maximum voltages, and then try to orient the part to that footprint.