The WDDX protocol is used for most client/server communications.
The ASDocs are located in lams_documents/UI_Design_Docs/apidoc/frameset.html http://dolly.uklams.net/lams/docs/frameset.html
View the client debugging window - press CTRL-ALT-? in the Flash window.
So far we have been using Flash Studio MX 2004. Sepy the Actionscript editor makes a great tool - bit buggy and does crash a bit. Monitoring the Eclipse Actionscript developer plug-ins. Could be a good alternative.
It seems that sometimes cached classes are not updated on compiling, this also affects when using the IDE's debugger and stepping through code. It seems to happen occasionaly, basically the solution is to delete the ASO cache from your local disk. That is all the files here:
\Macromedia\Flash MX 2004\en\Configuration\Classes\aso.
See this Macromedia technote for instructions. http://www.macromedia.com/cfusion/knowledgebase/index.cfm?id=tn_19045