Using auto-update for private plugins

Hi,

at the moment I’m developing a couple of new plugins which I intend to sell to some of my own customers. I still want to be able to provide updates for my customers though but I obviously can’t put my plugin in the WordPress plugin repository when I want to sell it myself.

I’ve tried tons of stuff throughout the past couple of days but I just can’t get it working.

I’ve tried following this tutorial: http://konstruktors.com/blog/wordpress/2538-automatic-updates-for-plugins-and-themes-hosted-outside-wordpress-extend/
And I’ve tried reading the chapter on auto-update in this book as well: http://www.amazon.com/dp/0470916222/?tag=stackoverfl08-20

Neither of those worked out for me.

I’ve also tried using get_transient('update-plugins') and set_transient('update-plugins') to tap into the plugin updater, but doesn’t give me a result either.

I’m not even sure if I’m doing it right.

I’ve got a testing plugin called “Designature Update Test” which is located in the folder “update-test”. The main plugin file is called update-test.php and it’s from this file I’m trying to call the update.

At the moment I’ve got the following code in update-test.php:

$up = get_transient('update_plugins');
$data = new stdClass;
$data->slug = 'update-test/update_test.php';
$data->new_version = '2.0';
$data->url = 'http://designature.dk/beta';
$data->package = 'http://designature.dk/api/plugins/update-test.zip';
$up->response['update-test/update_test.php'] = $data;

set_transient('update_plugins', $up);

The current version of the plugin installed is 1.0 and even though I set the “new_version” to 2.0 it still doesn’t show up.

Am I doing anything completely wrong? Or does anyone perhaps have a link that’ll show me how to do this?