While most (if not all) Windows Phone 7 smartphones can be bought SIM-free and without any carrier locks, some Windows Phone 7 devices feature a kind of network-lock which is even kind of supported by Microsoft. As a matter of fact, Microsoft has simplified the Windows Phone 7 settings way too much and users are totally unable to configure the MMS settings. If a network configuration isn't supported by the manufacturer, there's no official way for users to change it. However, now there was a homebrewed utility released which allows Samsung Omnia 7 and Samsung Focus customers to change the network settings - according to the used SIM card.
Exactly like the original Samsung app "Network Profile" which is available from the Samsung zone, which nevertheless most often fails to work if the carrier doesn't allow the use, this little utility allows it to select the correct communication profiles for mobile Internet (APN), messaging (MMS), etc. In addition, the utility even allows to enable "auto profile selection" - even if this functionality was also disabled by the carrier who sold the device - which means the device will automatically recognize and use the correct communication settings, according to the plugged-in SIM card.
However, since this is a homebrewed XAP file, it's unfortunately not available from Microsoft's Windows Phone 7 Marketplace but requires the unofficial side-load installation which therefore requires an application unlocked Windows Phone 7 device.
Nevertheless, we've just tested this utility with a T-Mobile Germany exclusive Samsung Omnia 7 (which is originally locked down to T-Mobile's settings only) and a O2 Germany as well as Vodafone Germany SIM card and we can confirm that it worked and the Omnia 7 was finally able to send and receive MMS messages!
However, we've also tested it with an LG Optimus 7 and as expected the utility isn't working on the LG Windows Phone 7.
Cheers ~ Arne