Access net via Automatic Configuration Script

I need to access a wsdl file from my java program. I have the url for the wsdl. I use wsdl4j to read it. The user informs me in advance if he is using a proxy. He provides port+ip OR Automatic Configuration Script address. port ip part done. Automatic Configuration Script creating problem.. dunno how to do it..

My limitation number one is that I can use only jdk 1.4.0_2 (or below!).
Number two, I am working behind a firewall. Internet Explorers need to use Automatic Configuration Script to access the net. The script address reads something like : "http://213.543.12.1/co-domain-intranet-internet.proxy". I cannot open the url directly, access denied.

Currently using the proxy IP and port the program works. I need to do the same using the script... Any suggestions? The code goes:

public void readWsdl(String wsdlUrl){
if(useUsingProxy){
String proxyHostStr = proxyHostTxtField.getText();
String proxyPortStr = proxyPortTxtField.getText();

Properties prop = System.getProperties();
prop.setProperty("http.proxyHost", proxyHostStr);
prop.setProperty("http.proxyPort", proxyPortStr);
}

try{
WSDLFactory wsdlFactory = WSDLFactory.newInstance();WSDLReader wsdlReader = wsdlFactory.newWSDLReader();
Definition definition = wsdlReader.readWSDL(wsdlURI);
}
catch(Exception expn){
System.out.println("problem in reading wsdl");
return;
}
}