Q: Why applications do not work under wifi with proxy?

Hello:

In my village there is a wifi installed that runs under a proxy with autentication: every user has his router at home and connects to the "general" wifi through a proxy with an username and password. I configure the wifi as follows: Wi-Fi --> Select the wifi --> I select Manual Proxy HTTP --> I type the server and port, enable authentication and type the username and password. Now, when I open Safari, I can navigate without problem. However, Safari is the only application that works: I cannot read my mail through the generic Mail application, nor enter in Facebook application, Twitter, Skype and so on. However, I can enter, for example, into Facebook through Safari.

We are some friends with the same problem, some of use have iPhone 3, others have iPhone 4 and I have iPod 2nd generation.

I guess that not all the applications of the device run using the proxy enabled in the Wi-Fi options but the should, shouldn't them? Does anybody know if there is any solution to this problem?

I hope I have explained clearly enough.

Thanks,

Maria