iPhone 4S Activation issues in Angola

[jsilva5000]

Hi Guys,

My name is Jorge Silva, and I am from Portugal (Lisbon).

We are having some issues with iPhones 4S activation in Angola.
We bought them in Lisbon for a project that we are implementing in Angola.

We tried with SIM cards form the following mobile operators:

Unitel and Movicel from Angola
TMN and Vodafone from Portugal

We always get an error message saying that the SIM card is not valid for the iPhone activation.

Any ideia?
Anyone knows if a specific firmware version for iPhoneis ncessary for Angola?

Many thanks for our help in Advance.

Best Regards,
Jorge