The welcome email for your Joyent Shared Accelerators account contains important login information and links to all the services you might use on the server. If you lose this email, you can resend it to yourself any time from within Virtualmin.
This will immediately generate a new welcome mail for you (based on the information Virtualmin carries for your account), and send it to the email address that you have stored on your Virtualmin profile (see how to change the Virtualmin email).