Flash AS3 and PHP [Ongoing]

Purpose: I want to add, search, and delete from a csv file on my server. Limitations: I only want to use Flash and PHP to edit the CSV file. No other programming language. What I Need: One button in an FLA. When this button is clicked, it appends a string to the CSV file. It must do this using a PHP file on the server that uses the 'Write' function in PHP [w,a] where a is for append. That is it. Nothing more. Acceptability Criteria: Clicking the button in the FLA [on my computer] will send the string of my choice 'i.e. var str:String = "Hello";' and write it to CSV. When I test it, it should not return an error [i.e. undefined]. PHP should echo back to Flash and should be traceable in Flash as a PHP var. I should be able to put my own URL to my CSV into the URL loader and PHP file and still get this result. Deliverable: I need one AS3 file and one PHP file.