I have added a ZenCart v1.3.8 to a site I am managing which uses a custom built CMS. I would like to add a direct link to the ZenCart admin interface from the admin interface of the CMS. There is already a similar link to a PhpList installation.

The Phplist link uses an href of the form ~/admin/?login="xxx"&password="xxx". I have tried a similar link for ZenCart but it just opens the login form and I have to enter the username and password. I would prefer it to login directly without having to input the details.

Can anyone suggest the correct syntax?