Accessing Nested DW (Not Composite)

I'm having issues trying to access a nested DW.  Can't use getChild() because I believe that only works for composite DWs. 

Have the main 'dw_1' and then within that a nested 'd_add'.  I tried creating a datastore and using the following code (and other variations that I got from Internet search) to get it to work but no luck - 'Error accessing external object property' in the code in the 'For Loop'

lds_temp = Create datastore
lds_temp.dataobject = 'address'
lds_temp.SetTransObject(SQLCA)
lds_temp.Retrieve()

dw_1.SetTransObject(SQLCA)

ll_rowcount = dw_1.retrieve()

FOR  ll_i = 1 to ll_rowcount

dw_1.object.d_add[ll_i].object.data.primary.current = lds_temp.object.data.primary.current
Next

Any suggestions would be greatly appreciated!!!!!

Thanks,

Dave