Package Manager connection and Software Updates of Digi ESP behind proxy

I’m currently trying to get the Digi ESP 5.0 runnable on ConnectCore 9M 2443. Since my system is behind a proxy that requires authentication i cannot neither search for packages and updates nor access the Digi help via Help->Help Contents. The environment variable http_proxy is set as follows: http_proxy=http://user:passwd@proxy.com. Also, the KDE network settings for the proxy are set to use environment variables. At this point all that what uses system settings (e.g. firefox) works properly. How can I get connection through my proxy?
I would be very grateful for a good advice

If you can, simply get hold of the ESP 5.2 distribution (this doesn’t auto-update from 5.0; you have to install it). I believe recent purchasers of 9M dev kits are automatically entitled to it.

Otherwise, download the patch from http://ftp1.digi.com/support/patches/DEL%2050%20Updates.htm which allows you to update from behind a proxy server

Thanks for the advice. Applying the update hasnt solved the problem. From now appears an input dialog where I have to enter my login data. Putting the right authorization stuff takes no effect and consequently the check for updates fails. However, I’ve installed the 5.2 version but the problem still remains.