Authentic hadith for “Allaahumma laka sumtu wa ala Rizqika Aftartu”?

I was talking to my friend other day and he mentioned me something which I was not aware of before; he told me that our Prophet (PBUH) never pray dua before keeping (sehri time) a fast and also when he breaks the fast he prays? Dhahaba adh dhamau wab tallatil urooqa wa thabatal ajru in shaa Allah? [Sunan Abu Dawood, Vol. 2, Number 2350; al-Baihaqi, 4/239; al-Hakakim, 1/422]. Is the above mentioned the right one (it is properly referenced too) because my whole family pray Allaahumma laka sumtu wa ala Rizqika Aftartu. And I was looking for any authentic hadith for above dua but did not find one.