You can use the UM JMS libraries to work with it via JMS in both directions
You CAN also bridge between UM native and JMS.
A few years back I wrote a C# native publisher that was consumed via JMS (in Integration server), and also wrote a C# subscriber, with a JMS publisher.
Some documentation was added post my work to help:
JMS Message Type Conversion (softwareag.com)
There were also some tech community articles I wrote that I can no longer locate - but these are probably out of date now anyway. Regardless I’ll sort through my archives and see what I can find 
#Universal-Messaging-Broker#webMethods