Ubuntu Networking :: 9.10 - Synaptic And Autoconfig Proxy Script

Using Ubuntu 9.10. I got a problem with the wired connection. I managed to fix it more or less. But now after I did about 2 days ago an apt-get update, I can't update through the Update Manager, nor install packages through the Synaptic Package Manager, nor install video drivers anymore. Using the terminal works: apt-get install, apt-get update and apt-get upgrade. I'm using a proxy (I'm connected to the network of my university, which uses a proxy) and a autoconfiguration script *.PAC.

I've never encountered such a problem - to be able to surf or use the terminal, but not the update/synaptic/divers manager. So I looked on the internet and found out that Synaptic has it's own network settings and doesn't care what proxy I've set in the Network Proxy. I don't recall ever having such a problem. I don't recall configuring the network preferences of Synaptic either (I just discovered them ). Another thing worth mentioning - I can use Synaptic and Update Manager ONLY if I run them from the terminal WITH sudo.

Code:
sudo synaptic
and
Code:
sudo update-manager
Only when doing so, the managers are able to connect to the internet. If I run only
Code:
synaptic
and
Code:
update-manager

And after being prompted for administrative privileges I enter the admin's password, they don't connect. So what I think happens is that Synaptic/Update Manager/Drivers Manager use somehow different network configuration than the one set in Network Proxy. Terminal on the other hand takes the proxy-settings directly from Network Proxy. The weird thing is that using terminal to call Synaptic for example make Synaptic accept the Network Proxy's settings. I looked in a couple of threads, where this ~/.bashrc was mentioned and adding export http_proxy="xxxx.yyyyyy.zzz" at the end of the file. But I still can't figure out what to do exactly. It's not a script, it's not something executable.