Proxy Server with Apache

I have a need to test simple http requests to an external webservice-
the application making the request passes a user, password, host and
port-

I can successfully make requests when I use no authentication (Can
pass any username/password from the calling server) but cannot get
authentication to work (Passing username and password)

I set the http.conf file as follows:

ProxyRequests On
ProxyVia On

<Proxy *>
order allow,deny
allow from all
deny from none
AuthName AddressCleansing
AuthType Basic
AuthUserFile "C:\users\htaccess.conf"
require valid-user
</Proxy>

I did run the httpasswd program to generate a user and he is populated
in the htaccess.conf file...

I am setting the httpd.conf file as follows with no authentication and
this works:
ProxyRequests On
ProxyVia On

<Proxy *>
Order deny,allow
Deny from all
Allow from <IpAddressFromCallingServer>
</Proxy>

Any thoughts.... ???