Catalyzes the transfer of an acetyl group to dTDP-D-Fucp3N to form dTDP-D-Fucp3NAc in the biosynthesis of dTDP-3-acetamido-3,6-dideoxy-alpha-D-galactose, a glycan chain of the S-layer. acetyl-CoA + dTDP-3-amino-3,6-dideoxy-alpha-D-galactopyranose = CoA + dTDP-3-acetamido-3,6-dideoxy-alpha-D-galactopyranose + H(+) kcat is 2.3 sec(-1) with dTDP-D-Fucp3N as substrate. kcat is 3.1 sec(-1) with acetyl-CoA as substrate. Belongs to the transferase hexapeptide repeat family.