Catalyzes the transfer of the carbamoyl group from carbamoyl phosphate to the delta-amino group of N(2)-acetyl-L-ornithine to produce N(2)-acetyl-L-citrulline. This is a step in an alternative arginine biosynthesis pathway. The enzyme has no activity with ornithine. carbamoyl phosphate + N(2)-acetyl-L-ornithine = H(+) + N(2)-acetyl-L-citrulline + phosphate Carboxylation at Lys-302 increases the catalytic activity of the enzyme. Amino-acid biosynthesis; L-arginine biosynthesis. Homotrimer. Belongs to the aspartate/ornithine carbamoyltransferase superfamily. AOTCase family.