I have two domains hosting in two different servers: domain1.com & domain2.com

I would like to forward "blog.domain1.com" to "blog2.domain2.com" which is a Wordpress blog using CNAME redirect.

Before I installed Wordpress.

blog.domain1.com (=redirect=>) blog2.domain2.com/index.htm
(working fine)

The browser will keep the URL (http://blog.domain1.com) even the index.htm is on domain2.com server.

However, after I installed Wordpress, the browser will change the URL to (http://blog2.domain2.com)

This is my current setup:

On domain1.com DNS:

blog.domain1.com CNAME redirect to domain2.com

on domain2.com .htaccess:

Options +FollowSymLinks 
RewriteEngine On 
RewriteCond  %{HTTP_HOST} ^blog\.domain1\.com 
RewriteRule ^(.*)$ http://blog2.domain2.com/$1 [R=301,L]

on blog2.domain2.com .htaccess:

DirectoryIndex index.php
<IfModule mod_rewrite.c> 
Options +FollowSymLinks
RewriteEngine On 
RewriteBase /blog2/ 
RewriteCond %{REQUEST_FILENAME} !-f 
RewriteCond %{REQUEST_FILENAME} !-d 
RewriteRule . /blog2/index.php [L]
</IfModule>

blog2.domain2.com is installed under domain2.com/blog2/

All I want to do is keeping the URL (blog.domain1.com) unchanged for the whole Wordpress redirect.

Thanks a lot.