Involved in the synthesis of mannosyl phosphorylinositol ceramide (PubMed:12954640). Catalyzes the addition of mannosyl to phosphorylinositol ceramide (PubMed:12954640). a 1D-myo-inositol-1-phospho-N-[(R)-2-hydroxy-very-long-chain fatty acyl]-(R)-4-hydroxysphingoid base + GDP-alpha-D-mannose = an alpha-D-mannosyl-(1<->6)-1D-myo-inositol-1-phospho-N-[(R)-2-hydroxy-very-long-chain fatty acyl]-(R)-4-hydroxysphingoid base + GDP + H(+) Heterodimer of CSH1 and CSG2. Exhibits a reduction in the synthesis of mannosylated sphingolipids. Present with 195 molecules/cell in log phase SD medium. Belongs to the glycosyltransferase 32 family.