Web Dispatcher: masking/hiding external URL

Hi,

I am configuring our Web Dispatcher to redirect to external URL with below scenario:

Web Dispatcher URL: http://wd.mycompany.com/EXT

External URL: http://www.external.com/

The URL redirection is working fine -  accessing http://wd.mycompany.com/EXT will be redirected to http://www.external.com, but browser is now showing http://www.external.com instead of http://wd.mycompany.com/EXT.

I understand we can do masking/hiding SAP back-end URL.

My question: is it possible to mask/hide external URL using Web Dispatcher? How to do that?

Regards,

Hari