Hey,
I know that I'm worming up old meat, but this is also a case for me. I have been planning to use SSI over RS485 (use one signal as a clock second as a input) but I don't think that there is a tool for doing this in vision. I have V430-J-B1 PLC.
Attached you can find SSI protocol descr. Do you think it is possible to comunicate it with V430 PLC?
SSI-opis.pdf