How to Obtains Default User or System Credentials for a Web Services Proxy running behind the Firewall

[ndskim]

Currently I have the Web Services Proxy code generated by the WSDL.Exe
command line. My Web app consists of ASP.NET in VB 2005 version.

Here is what I have in the sample code:

' Set Proxy Credentials to the current network DefaultCredentials.

With lds_WebService

..Proxy = System.Net.WebRequest.DefaultWebProxy()

..Proxy.Credentials = System.Net.CredentialCache.DefaultCredentials()

End With

' Now submit request to the server.

Try

' * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *

'

' 1. The line below will succeeded to send request to the Web Svr if

' I'm outside the Firewall, in public Internet.

'

' 2. However, If I'm inside of the Firewall and already authenticated with

' the Corporate domain, it will Throw exception because of the
Firewall credential.

' System.Net.CredentialCache.DefaultCredentials() always blank

' Domain, UserName, Password etc...

'

' * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *

lds_WebService.SubmitRequest("MyObject")

' Do other things.....

' Catch exception .

Catch Epx As Exception

Throw New Exception(Exp.Message)

End Try

My question is what is the appropriate way to get the default user
credentials that are compatible to use inside/outside the Firewall?

Any assistance is highly appreciated and thank for you time.

Ndskim.