Get the Change History of Notes block in BP screen

Hi All,

My requirement is to

1. Create Four new fields : Created By, Created on , Changed by, Changed on in Web UI in Accounts Overview.

2. Update These fields with the Name and Date field as below:

  a. When a BP is created, and when the Notes block is filled for the first time, Created by and Created On Fields should be updated.

  b. Only when the Notes Block of a BP is changed, Changed by and Changed on fields should be updated.

Any hint on how to achieve the 2nd functionality..

I tried using FM's CD_OLD_READ_POSITIONS, CHANGEDOCUMENT_READ_HEADERS and Tables : CDHDR & CDPOS.

But could not find any help !!

ANy help is highly appreciated. !!

Thanks in Advance !!!!