Static variable change does not take effect, nodeJS

I'm writing a little nodeJS based email server. I have a Request object, and in it there's one static variable that stores all the users and is defined like so:

Request.publicMemory = new Object();
Request.publicMemory.users = new Object();

Request.prototype.getPublicMemory = function() {
    return (Request.publicMemory);
};

I store User objects in it:

function User(params) {
    this.mails = new Array();
    this.sent = new Array();
    var details = new Object();
    details.username = params.username;
    details.password = params.password
    return;
}

As you can see there's also a static function that returns it.

Now, I can add uesrs and that change is actually made, but when I change anything in Request.publicMemory.usesrs[someuser] the change is always local to the function, and does not take effect in other places. Here's an example of how I do it:

function addMail(request) { 
    var users = request.getPublicMemory().users;
    var to = request.parameters['to'];
    users[to].mails.push(mail);
}

I've never used a static variable in nodeJS before, and I'm quite new to it so this might be silly, but I still can't solve it. Any ideas?

Thanks!