Catalysis of the reaction: lipopolysaccharide + UDP-N-acetylmannosaminouronate = N-acetyl-beta-D-mannosaminouronosyl-1,4-lipopolysaccharide + UDP.
UDP-N-acetyl-beta-D-mannosaminouronate:lipopolysaccharide N-acetyl-beta-D-mannosaminouronosyltransferase activity