Basic Auth in Window.Open

[organicg]

I have an image button on a page that calls a javascript:window.open(url). The url is on a MS Exchange server connected to our IIS Server.(It's popping up the Outlook Calendar) Exchange pops up the Basic Authentication login to the new window. I'm trying to avoid this and automatically authenticate the request by passing the username and password somehow.
I tried adding these headers to the outgoing response of the page that has the javascript but no luck:

Response.AppendHeader("basic-cookie", "[base64encoded UsernameAndPwd]=");
or:
Response.AppendHeader("Authorization","Basic " + "[base64encoded UsernameAndPwd]=");

but neither seem to work, the login window still pops up.

Anyone know if this can be done?