hEIRARCHY IN BAPI_PROJECT_MAINTAIN

HELLO experts,

i am using this BAPI BAPI_PROJECT_MAINTAIN for maintaining the herirachy for the WBS but whenver i am creating the wbse its not maintained in the proper level as i am using I_WBS_HIERARCHIE_TABLE for maintaining the heirarchy but its not working properly, kindly hepl me out in solving this problem ASAP

thanks