Korg Poly800/EX800 Users

HI there, new guy here - I saw something about the FM-800 mod where
the DCO-1 modulates the VCF and I am amazed how simple it is to
accomplish. Now I would like to do the same thing with the VCA for
amplitude modulation and DCO1>DCO2 FM w/adjustable feedback and maybe
even cross FM. Now here's the hitch: I have only accomplished the
first mentioned mod by following the instructions on this site:
http://www.synthmod.net/korg/fm800/ and though I know something about
electronics and soldering I just really, REALLY suck at reading
schematics, so if someone could point out for me where VCA, DCO1 and
DCO2 are and  the right spots to get said mods accomplished that would
be awesome. 

Greetings - Patrick