how to reverse payment key after cash flow reversal

Hi  Team,

I   have   done the following :

1) created a  facility

2) TBB1 -  ' pay only '  -    The  payment key is  created.   No  FI  posting happens since  'pay only ' is selected.

3) The  cash flows are  not  right,  so  I   reversed the flows in  FTR_EDIT  using the  'reverse '  option in the cash flow tab.  The  cash flow is reversed after this.

But the  payment keys are  not  reversed.   They  still  come up as open item in  F8BT.   It can get  paid wrongly in F111.

I  tried  TPM10,  but   as there is no  cash flow, it  does not  help.

Please  tell  on  how  to   make  reverse the  payment keys .

Thanks

kamala