large port declartaion in system c ?

Hi,
I am working on system C. I want to declare 256 input ports each of 1 bit.

I tried with sc_in<bool> d_in[256];

but when i call this module to other and want to assign d_in some value
e.g
module.d_in[dd];

where dd is as sc_signal<bool> dd[256];

compiler issues me error, or if i do some changes then compiler not issues me error but simulation not work.

I will be thank ul to you, if some one can help me regarding this, or can refer me some working example code.

Thanks again
Shahid