ToCTensor does not respect symmetry of tensor

If I try to convert a tensor object to a CTensor

DefTensor[F[i, j], M, Antisymmetric[{i, j}]];
Fc = ToCTensor[F, {ch, ch}]

The output is

CTensor[{{F[{1, ch}, {1, ch}] , F[{1, ch}, {2, ch}] , F[{1, ch}, {3, ch}]}, 
         {F[{2, ch}, {1, ch}] , F[{2, ch}, {2, ch}] , F[{2, ch}, {3, ch}]},
         {F[{3, ch}, {1, ch}] , F[{3, ch}, {2, ch}] , F[{3, ch}, {3, ch}]}}, 
           {ch, ch}, 0]

which is obviously not antisymmetric. I would have expected

CTensor[{{0 , F[{1, ch}, {2, ch}] ,  F[{1, ch}, {3, ch}]}, 
         {-F[{1, ch}, {2, ch}] , 0 , F[{2, ch}, {3, ch}]},
         {-F[{1, ch}, {3, ch}] , -F[{2, ch}, {3, ch}] , 0}},
           {ch, ch}, 0]

How do I keep antisymmetry in the co-ordinate basis? Thank you!