Not applicable

Proper handling of mileage reimbursement paid by client

I am new to QB, and I'm using the desktop version. I provide services to a state agency that reimburses mileage along with the fees for service that I receive. I receive a lump sum check that is a combination of fees and mileage. I would like to split the deposit into my income account and a mileage reimbursement account. How do I set up the mileage reimbursement account? And if I am on the wrong track here, what is the best way to handle this?