Reliable Messaging reference

I just reread ebXML's work on Reliable Messaging (see [1], Part II, Sec. 6, Reliable Messaging Module), and it looks like required reading for any discussion on this subject within our group (so that we don't spend a lot of time redoing what has already been done). 

Besides the specific syntax used, which belongs to ebXML and does not need to be duplicated, I am curious to know if people find deficiencies, or have any other type of observations, regarding the reliability model used.

Ugo

[1] http://www.oasis-open.org/committees/ebxml-msg/documents/ebMS_v2_0rev_c.pdf