MMS not working in iPhone4S when installing config profile with APN

Question

When we use the iPhone Configuration Utility (either the latest version or previous versions) to create a config profile with APN info, then install the profile to an iPhone4S, we noticed that MMS (multimedia messaging) was no longer working. This means we could not send or receive MMS messages. And this is MMS going over the MMS protocol (and not iMessage). We had not seen this before. We routinely do config profiles with APN info and have done for all iPhone models and iOS version before the new iPhone4S. Never had a problem with MMS or anything else. This is for iPhone4S devices in the AT&T network. It is easy to reproduce and you don't need an enterprise APN for that. In fact just a config profile with AT&T's APN settings will still break MMS when installed (other than the MMS, everything else works fine).
It does not appear an iOS 5 issue. iPhone4 (or iPhone3GS) with iOS 5 do not have this problem. It appears to be tied to the new iPhone4S hardware. The same configuration profile (with the APN info) works fine on iPhone4 with iOS 5 (MMS works fine), but when you put the very same configuration profile to an iPhone4S, MMS quits working.
Doing a network reset does not solve the problem. Only removing the profile fixes the MMS
Any ideas, explanations or workarounds?

Answer 1

I called the Apple care line, and eventually got to 4th tier support, where they declared that there must be an issue with the APN I'm using, regardless of the fact that none of the iPhone 3G, 3GS', and 4's in our office are experiencing this issue while using the same APN.  I guess I shouldn't be surprised about this, afterall who'd expect Apple to actually admit there's a "bug" in one of their products, especially since this is hapenning to a very small number of users on the 4S.  Getting to 4th tier support was free, but to be able to talk to someone who can actually investigate this issue will cost $700.
I offered to give them access to our private APN for testing, but they were "unable to do that sort of testing".  Additionally, we have tested using a public APN from AT&T (wap.cingular), and still experience the same issue.
Lastly,  I did some further digging, and I think it has something to do with PDP Context 2 not getting an IP address.  As a disclaimer, I have no clue what a PDP Context is, what it does, what it's for, but obviously MMS needs it.  Going into field test mode on the phone will allow you to see the PDP Contexts, and is where I got this info from.
On the iPhone 4S, without an APN profile installed, the PDP Contexts are listed 0-3.  These 4 contexts have values for an APN, and an IPv4 address, although context 0 and 2 are the only ones that have values in them.
When an APN profile isnt installed, MMS' can be sent, cellular internet doesn't work., the values are:
Context 0
IPv4:    ip is blank
APN:   phone (this is the default APN for the iphone 4s on att).
Context 2
IPv4:     has a valid public IP address
APN:     wap.cingular
When an APN profile is installed, MMS's can't be sent, but cellular internet does work, the values are:
Context 0:
IPv4:     Valid public IP address is present
APN:     Our enterprise APN
Context 2:
IPv4:     ip is  blank.
APN:     wap.cingular
It appears that when Context 2 has an IP address, MMS' are able to be sent.  One other interesting fact, on the iPhone 4, only 1 PDP Context is listed, while the 4S has 4 listed.
Hopefully this issue will be resolved in the 5.1 update, as this update contains a baseband update for the 4S, updating it from 1.0.14 to 1.2.01-1.  Unfortunately I don't have access to a 5.1 beta, otherwise I'd test this my self.  If anyone has access to the beta, and wants to test APN profiles/MMS send status, we'd greatly appreciate it!