several ways to do that:

myProc.frameRate; // read framerate
myProc.frameRate(10); // set framerate

if your embedded had a method like:
public void myMethod ( String _str )
{
 // do something with _str here ..
}
you could do:
myProc.myMethod("something"); // call a method inside myProc (has to be public)

another way is to share objects, for example:

String testString = "abc";
myProc.myString = testString;

so now myProc could write the string to the screen inside draw() for example.

have a look at how to write libraries to see how to register handlers:
http://dev.processing.org/libraries/

hope this get's you started ...
F

no, not an error in documentation. if you want to use PApplet methods then the object can be a PApplet. if you want to use methods from your object, then the PApplet has to be of that same type.

if you're going to use eclipse instead of the processing environment, i strongly recommend that you get a java book to study, which will cover this sort of thing.