I am a licensed agent.
The commission received is also income on your SCH C weather you receive a 1099-MISC or not. That commission "should" already be included in the cost basis of the property on the SCH E too. If it's not, then "make it so".
I do believe when working this through the SCH E, the program will specifically ask you for commissions paid and then it takes care of the math for you. However, you will still need to include it yourself as income on the SCH C.
