Marty, your characterization of the RFC2119 words gives me great pause. If you were correct, then we must erase these words from our vocabulary -- which certainly was not the intent of the RFC. I must strongly disagree concerning those words used in non-upper case (*must* as opposed to *MUST*). Standard usage in RFCs has been strictly with ALL CAPS. This has also been true throughout the development process of TRP/ebXML-MS and in all our discussions. However, just be sure, I went to the IETF and asked. The answers so far have been in favor of only ALL CAPS (see attached) invoking the definitions in 2119. They do acknowledge the confusion as you have cited. One interesting example was the word May -- the name of a month. Should this also be an RFC2119 key word? I'm sorry Marty, but the 2119 definitions only apply to ALL CAPS, unless we define otherwise in our specification. We have been VERY careful with these words and we have only used them (the ALL CAPS versions) when we really mean the 2119 definitions -- including our use of OPTIONAL. Regards, David. Note: If more responses come in from the IETF, I will be happy to forward them.