on p. 48 under the declarations of the OverrideAttributeIntegerValue() 
and OverrideAttributeStringValue() methods it is stated that it shall 
be an error to attempt to override any of the standard attributes 
as well as implementation defined attributes designated as read-only. 
However, it does not state what happens if an attribute that does not 
exist in the parameters database is attempted to be overridden. 

Should this be an error, should it be explicitly allowed, or should 
it be undefined, i.e., implementation defined?  Given the use of 
`override' in the name of these methods it sounds like it should be 
an error to attempt to override a non-existent attribute.  This would 
imply, though, that the user will not be able to add his own 
information in the form of new attributes to this database, but I 
don't think that is a big deal. 

> johnS: Let's make this an error as you suggest.