Description of problem:

Since "upgrading" to kde 4.2 konqueror no longer handles the NTLM challenge from the corporate proxy server, preventing all external web access.
Akregator is likewise borked.  This is a serious regression from the last kde 4.1 package.

Version-Release number of selected component (if applicable):
kdebase-4.2.0-2.fc10.i386

How reproducible:
Attempt to access any non-local URL with konqueror.

Actual results:

Proxy replies with "407 Authentication Required", and konqueror stops there.
I can provide tcpdump output if it helps.

Expected results:

On receipt of the 407 konqueror should try to find a suitable username/password in an available wallet or prompt the user for such, and retry with that, satisfying the proxy and allowing the connection to proceed.

Additional info:

The proxy is specified with "Configure - Konqueror/Proxy/Manual specify the proxy settings", which have been checked and verified to work with firefox, same as they did before the upgrade.  However using the auto-proxy url produces the same breakage.

I have tried clearing kwallet, reinitializing with known good passwords, restarting etc, to no effect.  I have cleared every cache I can find.