Programmatically set proxy (for both wifi and gprs/umts)

[valerino]

Hi,
i'm new to iphone developing. I need to write an application which programmatically setup a proxy for all the available connections (that said, gprs/umts and wifi).

Now, the standard Settings.app (from what i understood) sets the proxy only for wifi connection. And the CFNetworkCopySystemProxySettings returns just that (and, moreover, i couldnt find any function to save proxy settings)

So my questions are :

1) is there any API i can use to read / write proxy settings for all the available connection types (network locations) ?

2) if not, there's a way to write directly to /private/var/Preferences/SystemConfiguration/preferences.plist (this is the file which holds all the data) ? From my experiments, file can be read but not be written to using deserialization / serialization (maybe need suid....).

Note that this tool is being developed for non-jailbroken iphones.....

regards,
valerio