This is really two questions. I have been looking around trying to find out how to manipulates symbols in Illustrator using CSSDK.
First, I don't know how to do a simple task of something like hiding and showing layers in a symbol. So that all symbols instances reflect the change.
Second, I don't know where to find any documentation to help me figure that out on my own.
Is there anything out there?
(I just want to clarify, this is using CSSDK, I am not using the illustrator interface but coding an extension.)
Are you using Extension Builder? If so you can get help by going to Help > Help Contents in Eclipse. In particular you can get the full Illustrator CSAW library API reference by going to the Adobe Creative Suite Extension Builder > References > CSAW Library API Reference > com.adobe.illustrator.
If you don't have Extension Builder then you can also find the CSAW libraries' API reference at http://cssdk.host.adobe.com/sdk/1.5/docs/WebHelp/references/csawlib/index.html
You might also find the illustrator specific scripting guide of interest: http://cssdk.host.adobe.com/sdk/1.5/docs/WebHelp/app_notes/illustrator.htm (also in the E.B. help pages), in particular the overview of the scripting object model.
Generally you can do anything with the CSAW libraries that you can do with the Extendscript libraries, and the code is pretty much the same (at least any interactions with the DOM should basically be the same) - in this case you might be better off asking in the Illustrator scripting forum, and then porting any ExtendScript code that people give you to ActionScript. I'm not sure if you can edit the layers of a symbol - I couln't see any obvious way of doing anything other than removing and duplicating symbols through scripting, but I haven't done much Illustrator scripting, so as I said, I'd try asking in the Illustrator scripting forum instead.
Hope that helps,