Relocating a structure to external memory

I seem to have an issue when trying to define a structure to exsist at an external memory location. the struct overlays registers in an external chip communicating through through the EMI interface.

the struct needs to start at the base address of Bank 1 (0x62000000)of the external memory and is sequentially addressed from that base address.

I attempted to do it this way

SPC3 spc3 __at(0x62000000);

and this way

typedef struct
{

  char a;
  u8 newvar;
}SPC3 __at(0x62000000);

neither of these methods worked.

this locks up the linker for some time then gives me an error.

is there an easier way to overlay a struct to an external memory location??