If you tell me the (e.g., IBM System x3550 M3, x3650 M4, BladeCenter HS22) and your IMM firmware version , I can give you more specific guidance on whether a key is still available or how to enable what’s already there.
While not always required immediately, restarting the IMM is recommended to ensure all features are fully pushed to the interface. Shopping & Pricing ibm imm remote control activation key