That's the problem, even wireshark doesn't have a dissector working properly with those messages.

It recognizes all SCCP messages except the ones I've enumerated on my prior post.

Is there a way to buy from Cisco the information I need?

Based no my experience, no.

But if you subscribe the "developer support" program that is paid for, they *may* release certain informations to you.

Since the above is a pure speculation on my side, I think the best course of action is still 'studying' by yourself.