T777. I was given an allowence for car expensese on my T2200 that where not included on my T4, how do I enter these in the T77 form?

I am claiming for Car expensese on the T777Auto form. On my T2200 part B section 5 my employer paid me a vehicle allowence per km, this was not included on my T4. Where do I enter this information on the T777 so i can claim expensese excedding the allowence?