Correlation property names are odd, and the space of options is notextensible.

[Eric Johnson <eric@tibco.com>]

Target: Web services binding specification, WD 02

Description:
Current allowed names for "correlation" are "RequestMsgIDtoCorrelID", 
and "RequestCorrelIDToCorrelID".  These names are long, and yet oddly 
shortened.  Further, a "None" option is defined, it it is not clear 
whether this is meant to foreclose vendor specific notions of 
correlation, or to flag that a vendor specific correlation is defined 
elsewhere.

Proposal:
For the two defined correlation approaches, drop the redundant parts of 
the label, the "ToCorrelID", and "Request" parts, and remove 
abbreviations on the remainder, to yield "MessageID", and "CorrelationID".

Change the definition of the schema element to allow any QName here, so 
as to provide a way for vendors to identify their own correlation 
customizations.