Application Stack Builder - proxy error

Hello all,

I know that I am WAY behind the times here, but I am just now getting to
upgrade to 8.3. As I was reading through all of the installations I
realized that in order to install postgis now, you have to use the
Application Stack Builder and that this application has to access the
internet. Is there a way around this? First off, I am having issues
with connecting to the proxy. I can connect through my browser to the
xml file, but not by using the application. I looked at my options and
the internet browser is set to "auto detect" the proxy, which I am
assuming is the problem. Now I can go around and find out the proper
proxy and go through all kinds of hoops, but my second problem is that I
have some clients that are not going to be able to do this because the
servers that they load Postgres\postgis on do not have internet access
and they will not expose them. So, how do I load postgis into Postgres
without using Application Stack Builder; or how do I load it without
internet connection? This is a huge issue for me and I would appreciate
any help that anyone can provide.

Thanks in advance.