(keitai-l) How to identify that request is sent by Docomo gateway?

Can someone comment on the following issue, please:
 
Suppose I'm a content provider for iMode. I have some services (personal
info, customization, etc.) that rely on the handset ID passed by DoCoMo
gateway . The problem is that there's a chance that someone (impostor)
emulates the HTTP-request pretending to be DoCoMo gateway (passing
someone's handset ID) and gets access to this personal data. Is there a
way to prevent this? How can I determine that the incoming request
really is from DoCoMo gateway? If that's impossible, it means that
handset ID cannot be used for anything else than simple session
tracking. Is that correct?

Thanks.

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