how to bind mod_proxy to a specific ip address?

Hi,
following is my virtualhost configuration:

Listen 192.168.0.2:80
NameVirtualHost 192.168.0.2:80
<VirtualHost 192.168.0.2>
  ServerName        abc.mydomain.org
  ProxyPass         /  http://def.mydomain.org/
  ProxyPassReverse  /  http://def.mydomain.org/
</VirtualHost>

and the main ip address of my interface is 192.168.0.1 (eth0), and
192.168.0.2 is only an alias to the same interface (eth0:0), .
everything is fine, 192.168.0.2 listen to port 80, and the request to 
this ip address with host header abc.mydomain.org will be proxied to 
def.mydomain.org. The only problem is that def.mydomain.org get 
http request from ip address 192.168.0.1 , and not from 192.168.0.2.
So, how can I tell apache to use 192.168.0.2 instead of 192.168.0.1
if it makes http request to def.mydomain.org ? 

thanks for any help,
cahya.