Catalysis of the reaction: N-acetylneuraminyl-2,3-alpha-D-galactosyl-1,4-beta-D-glucosylceramide + UDP-N-acetylgalactosamine = N-acetyl-beta-D-galactosaminyl-1,4-(N-acetyl-alpha-neuraminyl-2,3)-beta-D-galactosyl-1,4-beta-D-glucosylceramide + UDP.
UDP-N-acetyl-D-galactosamine:N-acetylneuraminyl-2,3-alpha-D-galactosyl-1,4-beta-D-glucosylceramide beta-1,4-N-acetylgalactosaminyltransferase activity