Currently the administrator can upload custom .iso for the customer to use. There is no way for the customer to upload an .iso without contacting the admin for support. This makes it impossible for a customer to build certain kinds of servers, as they cannot automate the process of uploading a new image and rebooting the machine (e.g. self-healing / phoenix servers).
Please add an option to the customer web interface to upload an .iso file so that it overwrites a single .iso per customer. The .iso selection dropdown could then be used to select "uploaded image" so that the virtual machine could be installed from it.