Having reviewed SAG's documentation, it may be more straightforward to generate the HWM report via an Adabas utility rather than AOS.
But this still doesn't satisfy your request for direct access to the information.
A batch job that generates and parses the HWM report can be scheduled, as previously suggested, or triggered by an online user, where that user is a Web service. Once the information is in an Adabas database, there are several paths available to a Web service: Remote Procedure Call
and SOA Gateway
come to mind.