alpha-D-Man-(1->2)-alpha-D-Man-(1->3)-alpha-D-Gal-di-trans,octa-cis-undecaprenyl diphosphate + dTDP-beta-L-rhamnose = alpha-L-Rha-(1->2)-alpha-D-Man-(1->2)-alpha-D-Man-(1->3)-alpha-D-Gal-di-trans,octa-cis-undecaprenyl diphosphate + dTDP + H(+) — reaction