Catalyzes the conversion of UDP-2,4,6-trideoxy-2-acetamido-4-amino glucose to UDP-2,4,6-trideoxy-2,4-diacetamido glucose, commonly known as UDP-N,N'-diacetylbacillosamine (UDP-diNAcBac). acetyl-CoA + UDP-N-acetylbacillosamine = CoA + H(+) + UDP-N,N'-diacetylbacillosamine Forms oligomers. Repressed by SinR. Insertion mutant shows decreased efficiency of biofilm formation. Disruption affects swarming motility. Belongs to the transferase hexapeptide repeat family.