Run two websites with different host name in IISExpress

Hi,

Here goes the details of my problem:

Requirement: My client wants to host two websites with very similar content (for Australia and New Zealand) under one Umbraco installation. There will be a few pages that would be different (say contact us) from one another in the two site. Otherwise most content is identical. I have checked Umbraco and this is possible and configured easily. But I want to do a complete testing (locally) before I make the changes in production. The issue is related to configuring the test environment.

Development Environment: Unfortunately I am using a Windows XP machine with IIS 5.1 which is not good for testing. Can't use WebMatrix as Windows 7 is mimimum requirement for that. So I decided to configure IISExpress and Umbraco as per the following links:

http://umbraco.com/help-and-support/video-tutorials/umbraco-fundamentals/running-multiple-sites.aspx

http://our.umbraco.org/wiki/recommendations/recommended-reading-for-web-developers/webmatrix-running-multiple-sites-in-one-umbraco-instance

The applicationhost.config file has the following modifications:

<bindings>
      <!--<binding protocol="http" bindingInformation="*:15586:localhost" />-->
      <binding protocol="http" bindingInformation="*:15586:au.testsite.local" />
      <binding protocol="http" bindingInformation="*:15586:nz.testsite.local" />
</bindings>

The website is running as a ASP.Net website (Not an website application).

Problem: Both AU and NZ hostnames works but content is always from AU site (even on the NZ host). I suspect this is an IISExpress promlem (not an Umbraco) one. Is the identical port number causing the issue?

Any suggestions? 

Thanks,

Sudipta