Re: converting illy files from RGB to black only
If you are talking about RGB Black /0/0/0) you can use Acrobats Color Conversion tool using the option "Preserve Black Objects". If you have to perform this action more often, you can create a Preflight Fixup that carries out this type of conversion on a simple click of the button.
If you also need to convert RGB grays (value of R=G=B) you have to use 3rd party products like already mentioned. callas pdfToolbox (Plug-in or Server) being also a great tool when it comes to easy color conversion.
Regards,
Peter