Accessing messages from a JMS queue

I started this question on SAG-L, and Rolf already responded that EntireX cannot integrate with an external JMS queue, so my question will be broader.

What is proposed as a design is to have an external SOA layer place messages on a JMS queue (rather than call a web service) in case such a data request comes in during our maintenance window when EntireX and everything on the mainframe is unavailable. Such messages then can persist until the Broker, Adabas, etc is available for processing these messages.

Is there a way with Adabas, Natural and EntireX to support this kind of design?

I know EntireX can function as a JMS queue but if EntireX is not available, it cannot.

How would any of you solve this problem with this toolset?