Add document header text (BKPF-BKTXT) to dynamic selection in FB03,FBL3N,FAGLL03

Requirement
Doc. Header Text to be added in the dynamic selection in FB03, FAGLL03 etc.

Solution
Refer to the reply from Jeccas_DJ on the following SDN thread
https://forums.sdn.sap.com/thread.jspa?threadID=357594&tstart=0