Problems with closed proxy

[rumpage]

Hello there!

I have some problems with a closed proxy server at work.

It uses some kind of auto-configuration script called *.pac
If I use the script in IE everything works perfectly (besides IE that is) but if I try the script in Firefox (the script or the proxy server address) it prompts me for a username and a password.

Since I don't require to enter a username and password in IE it shouln't be so hard to get the credentials one way or another, or?

I can't display the script right now (can post it tomorrow).
Does anyone have an idea on how to use the proxy with firefox?

Thanks
Jonathan

[rumpage]

The script looks similiar to this:
function FindProxyForURL(url, host) {
if(isInNet(host, "y.y.y.y", "255.255.255.255"))
return "DIRECT";
if(isInNet(myIpAddress(), "x.x.x.x", "255.255.255.128"))
return "PROXY proxy.xXx.net:3128";
if(isInNet(host, "127.0.0.1", "255.255.255.255") ||
isInNet(host, "10.0.0.0", "255.0.0.0") ||
isInNet(host, "172.16.0.0", "255.240.0.0") ||
isInNet(host, "192.168.0.0", "255.255.0.0") ||
isInNet(host, "z.z.z.z", "255.255.255.0") ||
isInNet(host, "c.c.c.c", "255.255.0.0"))
return "DIRECT";
else
return "PROXY proxy.xXx.net:3128";
}