cost element

I am developing a cost center. where i am extracting cost center and object number from

CSKS table.

Using the Object I am extracting Cost element...

loop at itab.
  l_tabix = sy-tabix.
  select single kstar ebeln from covp
         into  (covp-kstar , covp-ebeln)
         where kokrs = p_kokrs
         and   objnr = gt_cc-objnr
         and   gjahr = p_fyear
         and   perio in s_period.
  if sy-subrc = 0.
    itab-kstar = covp-kstar.
    itab-ebeln = covp-ebeln.
    modify itab index sy-tabix.
  endif.
endloop.

The problem is a object number can have any number of cost elements associated with it....

this part however is retreiving only 1 cost element...

Please let me know how to fix this problem...