Dear All,
 Finally I had successfully up my tunnel, my heartiest thanks to all for participating this topics and giving your valuable ideas.
 
 Following is the solution which we found after our experiments when we upgrading firmware from 2.8 to 3
 Solution is based on my following scenario
 Main office FGT100A old firmware 2.8 MR11 upgraded to 3.00 build 0477 mode NAT
 Branch office FGT50A old firmware 2.8 upgraded to 3.0 build 400, mode transparent, connecting through internet using DSL
 Brach office connecting to main office no connection needs main office to branch office.
 Following is VPN config before upgrading
 FGT 50A
 Remote Gateway: Static IP Address
 IP Address: Public IP of FGT100A
 
 FGT100A
 Remote Gateway: Dynamic DNS
 Dynamic DNS: <blanks>
 
 Following changes we need to do when we upgrading to 3.0
 No changes need in FGT50A
 In FGT100A Dynamic DNS need value (I did a trick to get the DNS value by typing tracert <incoming ip address of FGT50A> in command prompt) 
 
 Thanks once again to all
 
 Sabu Thomas, MBA, CISM,CISA 
 IT Manager
 Minako General Trading CO LLC
 Dubai, U.A.E
 sabu@minako.ae
 www.minako.ae