The reg-apps makes use of the velocity library on several occasions. Velocity is a templating engine. It makes use of variables that are defined as an environmet for the template rendering process. These variables are set if they are available at the point of the rendering. Ie. the e-mail template, which can be sent on the initial user creation, only contains the user object. As for the e-mail template, which can be sent on a service registration, contains the user, service and regisry object.