I am upgrading from CSM 3.6 to WFBS Advanced 5.0. How do I get the additional AC for IMHS?
You need to contact Customer Service to request for the Registration Key (RK) to register the IMHS account. After you register your IMHS RK, you will receive an email with instructions on how to access the IMHS console and redirect MX records. Refer to this solution: Instructions for upgrading to WFBS Advanced 5.0 / 5.1 and activating a free IMHS account.