Angel Rivera and Mike Cregger of IBM have published a support document titled:
Using SSL TLS to connect two MQ queue managers in MQ 7.5 and MQ 8.0 / MQ 9.0 using self-signed certificates
The document provides step-by-step details for connecting a WebSphere MQ V7.5 queue manager in one platform (Windows) to a V8.0 queue manager running on another platform (Linux), using SSL TLS self-signed certificates.
Note: I have not tested the information in the document.
I have put a local link to the PDF here, in case IBM reshuffles their web site in the page disappears.
Regards,
Roger Lacroix
Capitalware Inc.