Schema problem with encryption in the AS4 draft

[Theo Kramer <theo@flame.co.za>]

I have received the following from Mike O'Connell (senior developer) involved in implementing our AS4 light client and adapting our MSH for AS4 support.

The server has strict XML Schema validation ON and this has raised a question (and a number of exceptions):

The WSS 1.1 spec allows for arbitrary XML elements to be encrypted and signed however the ebMS schema ('ebms-header-3_0-200704.xsd') does not.

The only element that allows for insertion of the 'wsu:id' attribute is 'eb:Messaging' since it has the 'headerExtension' attribute (which allows for 'xsd:anyAttribute'), 'wsu:id' is the ID reference used when applying WSS1.1 security to arbitrary elements. 

Now - I cannot encrypt the entire 'eb:Messaging' element because of the following from AS4-profile draft and in reference to ebMS v3.0, Section 7.4:

AS4 MSH implementations are(sic) SHALL NOT encrypt the eb:PartyInfo section of the eb:Messaging header. Other child elements of the eb:Messaging header MAY be encrypted or left unencrypted as defined by trading partner agreements or collaboration profiles.

The only way to bypass this issue is to turn XML Schema validation OFF, which defeats the whole purpose of XML Schema in the first place.

Your comments/input on this appreciated...

-- 
Regards
Theo