how to get service entry sheet , PO against a service for a WBS

hello all,

in CJ20N for a given WBS,

to get services PLAN details(like service qty and service plan cost),

i used following code,

SELECT pspnr
          post1
          posid
          werks
          prctr
          fkstl
          psphi
          belkz
          loevm
          vernr
          verna
          FROM prps
          INTO TABLE it_prps
          WHERE posid = p_posid.
 


if it_prps is not INITIAL.


SELECT projn
            vornr
            ltxa1
            packno
            matkl
            STEUS
            banfn
            bnfpo
            loekz
            from afvc
            INTO CORRESPONDING FIELDS OF TABLE it_afvc
            FOR ALL ENTRIES IN it_prps
            WHERE projn = it_prps-pspnr
            and loekz ne 'X'.




endif.


DELETE lit_afvc WHERE packno IS INITIAL.
 
 DELETE ADJACENT DUPLICATES FROM lit_afvc COMPARING packno.
 
 if lit_afvc[] is NOT INITIAL.
 
    SELECT packno                    " Package number
           fpackno                   " Parent package number
           FROM eslh
           INTO TABLE it_eslh
           FOR ALL ENTRIES IN lit_afvc
           WHERE fpackno EQ lit_afvc-packno.
 
 
  endif.
 
 
  if it_eslh[] is NOT INITIAL.
 
    SELECT packno                  " Package number
           introw                  " Line Number
           srvpos                  " Activity Number
           menge                   " Quantity with Sign
           meins                   " Base Unit of Measure
           brtwr                   " Gross Price
           netwr
           ktext1                  " Short Text
           tbtwr                   " Gross Price
           FROM esll
           INTO CORRESPONDING FIELDS OF TABLE it_esll
           FOR ALL ENTRIES IN it_eslh
           WHERE packno EQ it_eslh-packno
           AND srvpos NE ''.
 
  endif.
 
 
 sort it_esll by srvpos.

from the above code i could get the service plan qty and plan cost,

but my question is how do i get services actual qty and actual cost (i.e PO and Service entry sheet ) are created against it...

from AFVC i can get purchase requisition number, if i pass PR no to table EBAN i can get PO number,

after this how do i proceed.

or is there any FM or BAPI to get these details...

thanks in advance....