Read standard mesage with value

hi frnd.

         i have a requirement.After astandard trnsaction 'tm_51'  data save to standard table VTBFHAZU with unique field RFHA FIELD(FINANCIAL TRANSACTION).I have to store the uniue field's value after each transaction to ztable.As there is no effective exit /badi. so i need to capture the data from message genarated after standard transaction.

ex.message showing :-- transaction 10000011 created.

                                                                          i need to capture '10000011' value. Is it possible to capture messge value genarated after transaction.

                PLS HELP ME

                REGARD SUDIP.