I have a requirement where I need send the link of an assignment in an email to end user (anonymous user) and when that user clicks on the link it will take the user to the embedded mashup in an html page which will basically use the assignment key to display the respective assignment for the user to take action. For this it seems I can  use "Open an Assignment" action in Mashup to open the assignment anonymously and perform on it. Can somebody help in sharing the details on how to pass the assignment key dynamically in the Mashup as shown above?