RosettaNet Retry Parameter not Expressible in BPSS or CPP/A

Existing RosettaNet PIPs do not require exactly once delivery semantics.
Asynchronous PIPs have a Retry parameter that governs how many additional
retries a sender will send a message, if it has not received a Receipt
Acknowledgement signal from the other party.

Currently, BPSS does not allow for the specification of a retry count. At
the CPP/A level, the only available retry parameter is associated with
reliable messaging. It is not clear if RosettaNet should always use reliable
messaging for all PIPs.

Ideally, the DocExchange element should carry an alternate Retry element
that is not tied to reliable messaging. Otherwise, it will be great fi
extension mechanisms whereby namespace qualified extension
elements/attributes can be added. This is an approach that is used both in
SOAP and in the Message Service to provide extensibility.

-Arvola