AX 2009 Technical - Dynamics Ax Enterprise Portal Upgrade

Problem description
I have a partner who developed a portal on Dynamics AX 4 Enterprise Portal, Is it possible to upgrade the developed code from Dynamics AX 4 Enterprise Portal to Dynamics Ax 2009 Enterprise Portal?
Is there any best practice documents to upgrade the developed code?

Greatly appreciate your help.

I really appreciate your help in the below inquiry as I haven't received any answer:

I have a partner who developed a portal on Dynamics AX 4 Enterprise Portal, Is it possible to upgrade the developed code from Dynamics AX 4 Enterprise Portal to Dynamics Ax 2009 Enterprise Portal?
Is there any best practice documents to upgrade the developed code?

Greatly appreciate your help.

Response#1
As best I know, someone please correct me if I’m wrong, the changes between 4.0 and 2009 are significant and there’s no easy upgrade path. I believe bottom line is they basically need to recreate the customizations

Response#2
You can use the SysEPWebFormConverter to upgrade web forms:

http://msdn.microsoft.com/en-us/library/cc615339.aspx

http://msdn.microsoft.com/en-us/library/cc620983.aspx