FMX I can't get my head around LoadVars for saving data!

[font=verdana, arial, helvetica][size=2]I’m using Flash MX (2002) and I need to get my variable values saved to a server each time my test subjects run and finish my swf/fla (PHP scripts and a .txt file on the server are being worked on, but that’s a different nightmare!). I’m pretty sure I should use LoadVars, NOT SharedObject for this data capture right?. The data must not be overwritten each time over the course of a few months of data collection.

The 3 variables are: username (name of the user), counter (this keeps track of which version the user chooses from the start menu), numcorrect (keeps track of the number of times the <right> arrow key is pressed).

2 main problems:[/size][/font]
[font=verdana, arial, helvetica][size=2]I don’t know where to put in the LoadVars obj (in the AS code of “finaldisplay” frame?) AND I don’t know how to build/format the LoadVars object to capture the data in the 3 variables I listed above.

I’ve got several Flash books and have done online tutorials, so for something so simple (3 lousy variables!)…why is my life so miserable?

Here’s my zipped .fla. Will greatly appreciate any help.