Initializing a struct

Hi,
I am trying to initialize a struct, but I get the following error:

Error #29: Expected an expression

typedef struct
  {
    atp V1;
    atp V2;
    atp V3;
    atp V4;
   } tosh_at;


tosh_at tosh_options
={
  .V1 = 12,
  .V3 = 5,
 };

Can someone please help me. Thanks in advance.