Two jobs in one.

My article about rheumatic diseases is well written and I got a lot of nice comments on it. The client is very satisfied and he even asked me if I can write more articles for him in the future. I discussed this with my boss and my boss said it was okay but he proposed to take care of the payments like the way is is going right now. But that was not what the client meant but he understood that I can not write for him as I am still at work for my boss who pays me a lot. So from now on I will write for the client in the hours I am working for my boss and My boss will send him an invoice.