How can I add activation key when I became your IP partner?

As an IP partner, you cannot create activation keys.

You would add server IP into the partner interface, and then use:

# sh cldeploy.sh -i

to convert the server to CloudLinux;

or

# clnreg_ks --force

to register existing CL server.

This works only with servers with public IP address or 1:1 NAT.