JWS fails to detect ".ins" type of auto-proxy config if different ext being used

FULL PRODUCT VERSION :
java version "1.6.0_01"
Java(TM) SE Runtime Environment (build 1.6.0_01-b06)
Java HotSpot(TM) Client VM (build 1.6.0_01-b06, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
We uses IEAK ins file format for autoproxy configuration, however this file is being generated automatically via a cgi script and as a result the URL file is ending in ".cgi" rather then the ".ins" file.

In the com.sun.deploy.net.proxy.AbstractAutoProxyHandler.init method, the code actually uses the extension of the file pointed to by URL to determine whether it is an ins file or a javascript file. As a result Java Webstart fails to parse our autoproxy configuration file.

A better way for detecting whether the configuration file is ".ins" format or javascript is to use the MIME type from the web server. Java deployment code should check the configuration file's mime type to be "application/x-Internet-signup" rather then just checking the extension

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1) Setup a valid IEAK profile file
2) Serve this file on an webserver, however the file extension should be changed to something other then ".ins" and setup the webserver/cgi script such that this file is returned with a MIME type of "application/x-Internet-signup"
3) In Internet Explorer, go to Tools->Internet Options->Connections->Lan Settings->Automatic Configuration box, check automatic configuration script pointing to the URL that you have the IEAK profile being setup
4) In the Java Control panel, check the network settings so that it is using the browser settings.
5) Run any Java Webstart application, and you will find that it

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The Java Webstart application should start correctly
ACTUAL -
A dialog pops up with tile "Microsoft JScrip compilation error" saying "Expected ';'". This is because the deployment code treats the automatic configuration file as a javascript rather then a IEAK profile script.


ERROR MESSAGES/STACK TRACES THAT OCCUR :
A dialog pops up with tile "Microsoft JScrip compilation error" saying "Expected ';'".

REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
Make sure the URL to obtain the IEAK profile configuration ended in ".ins"