Question:

How to configure multiple AX 4.0 Enterprise Portal sites on the same web server each pointing to a different instance of the .NET Business Connector, each with a different configuration pointing to different AOS?

Answer:

By default , EP connects to the default configuration stored in the registry on the server.For the second EP on the same web server, create a new IIS virtual server in IIS and enable SharePoint and EP on this IIS virtual server as well.  Make sure they use differnet app pools ( even if the Identity / BC proxy account is the same).

On the Web server, make the following edits to the Web.config file in the wwwroot folder (for example, C:\inetpub\wwwroot where the Second Web server is installed in the C: drive):

 1) Add the Microsoft.Dynamics section group under <configSections>. Add the following text:

<sectionGroup name="Microsoft.Dynamics">

<section name="Session" type="System.Configuration.SingleTagSectionHandler, System, Version=1.0.5000.0, Culture=neutral,PublicKeyToken=b77a5c561934e089" />

</sectionGroup>

2. Add the following Microsoft.Dynamics element under </system.web>. Add the following text to the file:

 <Microsoft.Dynamics>

     <Session Timeout="15" Configuration="C:\Inetpub\wwwroot\axapta.axc" />

 </Microsoft.Dynamics>

You can export the AX configuration pointing to the second AOS to a file  and refer it in the second step.

Note :

(1) Make sure you have two diferent app pools for these two IIS web sites even if the business connector proxy account is the same.
(2) Make sure the SharePoint site is registered in AX for the right AOS instance.( Administration -> Setup -> Internet -> Enterprise Portal -> Web sites)
(3) For Microsoft Dynamics Ax 2009, make sure both IIS Websites physical directoy ( for ex. c:\inetpub\wwwroot\vss\virtual directories\80\app_code) contains the "proxy" folder with proxy files. These files are generated for X++ classes used by EP when EP setup is run. If one of the virtual directory app_code folder does not have proxy files, you can either generate them manually from Ax Client -> Tools -> Development Tools -> Web Development tools -> Proxies or copy them from the other virutal directory if that exists