extract memory value in systemC

Hi all,

 I have 2 files. 

In file A.vhd, I model a memory using "type t_mem is array(conv_integer(BASE) to conv_integer(TOP-1)) of std_logic_vector(7 downto 0);     variable mem : t_mem;".

In file B.cpp, I use "rtl_mem_value.observe_foreign_signal(memory_path)" to extract memory value, but I get "ncsim: *W,SCOOMR: Expecting port, signal, or net for out-of-module connection".

 Can anyone tell me how I can extract memory values?

Thanks