Yes, you can save struct.

Before you call game_save(), you must call the add_struct() to add an existing struct to it.

Example:
typedef struct STRUCTURE
{
var a;
int b;
}STRUCTURE;

STRUCTURE* mystruct={a=1; b=2;}

....

void main()
{
...
add_struct(mystruct,sizeof(STRUCTURE));
...
...
game_save("SAVE",1,SV_STRUCT);
}