If the server was originally purchased with the IMM advanced feature, the key may already be documented:
Once you have the .key file, follow these steps to activate the features on your server: Ibm Imm Activation Key
Organizations purchase the feature license through IBM or an authorized Business Partner. The entitlement is recorded in the IBM Entitlement System. If the server was originally purchased with the
Mount local ISO files or USB drives as if they were physically connected to the server. Ibm Imm Activation Key