在apprequest php中读取数据参数

This is my first question and in Stackoverflow although i must say that this is super interesting and useful. SO back to the point :

I want to make a facebook apprequest inviting people to join my app by doing so the person that accepted the requested and the person that generate it will gain points towards a prize.

This is my code :

function amigo(id){
    FB.ui({method: 'apprequests', message: 'AppMessage', title: 'reqTitle' , data: '<?php echo "fuente=".$id?>'});
    } // where fuente = my facebook uid

i would like to read the data parameter in php so i can look at my DB for that UID and assign the points but i have no idea how to do so . I have read the facebook API but the true is that i have not being able to understand that part.

Any help would be greatly appreciated since i am running against the delivery clock.

Thanks,

I implemented it as follows in Javascript:

function share() {
    function doAfter(r) {
        if(r && r.to) {
            var yourUid = '<your_db_id>';
            // r.to is an array of friends ids that where chosen using 'apprequests'
        }
        else {
            // handle error
        }
    }
    FB.ui({
        method: 'apprequests',
        message: 'AppMessage',
        title: 'reqTitle'
    }, doAfter);
}

You should Check this link from This Question for more information.