We are a mobile network operator (MNO). We are not able to activate iMessage service through SMS.. it can be activated using the email account as a reference, which uses internet to connect, but not SMS.
The initial issue we had since we launched the network is that our REG-REQ messages were not responded by Apple, or we were not receiving them. The REG-REQ message is sent by the iPhone towards a +44 destination. We've tried different SMS Centers and it didn't make much difference.
We recently switch to another SMSC, and very interesting is that we started to receive the REG-RESP messages from Apple, but now they are presented / displayed on the phones just a standard text message, instead of being treated as a silent sms, and picked up by the application on the iphone. Because of this we filtered inbound sms from most of the source numbers that Apple used for REG-RESP so we wouldn't have our customers spammed.
Why now when we finally get the REG-RESP messages they are presented as a standard SMS instead of silent SMS?