Catalysis of the reaction: alpha-D-man-(1->2)-alpha-D-Man-(1->2)-alpha-D-Man-(1->3)-(alpha-D-Man-(1->2)-alpha-D-Man-(1->3)-(alpha-D-Man-(1->6))-alpha-D-Man-(1->6))-beta-D-Man-(1->4)-beta-D-GlcNAc-(1->4)-D-GlcNAc-diphosphodolichol + dolichyl D-mannosyl phosphate = H+ + alpha-D-Man-(1->2)-alpha-D-Man-(1->2)-alpha-D-Man-(1->3)--beta-D-Man-(1->4)-beta-D-GlcNAc-(1->4)-D-GlcNAc-diphosphodolichol + dolichyl phosphate.
dol-P-Man:Man(8)GlcNAc(2)-PP-Dol alpha-1,2-mannosyltransferase activity