(PRO) XML Component Variables

Hi! Another problem I have a problem with!!

I am using an xml connection component. I have a simple problem when I declare variables in this.

Example:

var greetings:String = "hello"
trace(greetings) //returns hello
trace(this.greetings) //returns undefined
trace(URL) //returns example.xml
trace(this.URL) //returns example.xml

Just to show you, it is only in the variables that I delcare.
Are the variables stored within another place, or something?