Hi Praveen,Mark and Suhale,
Thanks alot for your inputs..
To make my requirement simple, I have selcted this approach
1) Decode Base64 String and place generated files into PI local folder
2) read files with other interface and map it back to SAP system.
Now I achieved part 1.
and for second part, I have opened other thread as its going into other discussions
http://scn.sap.com/thread/3763584
Regards
Siri