I reaffirmed a car loan and it's the same - it doesn't report after the bankruptcy. It's pretty common, and there really isn't much you can do except dispute with the bureaus. However, since the creditor isn't reporting, you'll have to keep disputing it every few months to keep it on your credit.
For some reason, when creditors stop reporting due to a BK, they never start reporting again once the debt is reaffirmed.