Web Service call through Webproxy (bypass doesn't work)

[Armin Prosch]

Hi,

we call a web service in an intranet environment. The target host is
bypassed as of the IE setting. We retrieve the system proxy settings through
"myService.Proxy = WebRequest.GetSystemWebProxy()". The host is in the
isBypassed list of the proxy object. The proxy credentials are the default
credentials of the login account (DefaultCredentials) and this account is
able to browse to the web service via IE.
But when we want to connect to the web service on this host the web proxy is
still queried. The whole request is cancelled due to authentication problems
on the web proxy.
If we set the "myService.Proxy = null" the request also didn't work (proxy
authentication required).
It only works when we use

<system.net>
<defaultProxy>
<proxy usesystemdefault="False"/>
</defaultProxy>
</system.net>

in the app settings.

Does somebody know whats the problem with setting the web proxy through
code? Why is the proxy queried even if the target host is in the bypass list?
Do we miss something here?
Thanks,