Basic Authentication

Hello
   I am a newbie to HTTP and writing an http client
application. I need to authenticate to a server which
is protected by basic authentication. But to connect
to the original server I need to connect to a proxy
which is also protected by basic authentication.

What I need to do here is to send the base-64 encoded
authentication header as part of the request. But
since the this has to be passed at two levels, can I
pass two values for the header at the same time? one
for the proxy and the other for the actual server?
Otherwise I will get the challenge back from one of
these servers right?

I also wanted to know how valid is this scenario.

Thanks for any help,
dw


__________________________________
Do you Yahoo!?
The New Yahoo! Shopping - with improved product search
http://shopping.yahoo.com