Miguel,
This might not be the right place to get the help you are looking for. You can reach out to the SAG Sales folks for the client and they will be able to assist you properly with your needs.
Having said that, SAG ESB(webMethods) comes with an in-built messaging product. It could either be the webMethods Broker or SAG Universal Messaging server(UMS). If your solution is looking to bridge to webMethods over JMS then you can connect using the JMS jars that comes with Broker or UMS installation(using connection factories). For Broker there is a Java/.NET API available and same is the case with UMS. You could also connect to UMS over web and mobile, if your client has the license for it.
There are different ways to interact with webMethods other than JMS… SOAP\REST\Files\Integration Server Java.NET API calls\Schedule Jobs etc.
#webMethods#Integration-Server-and-ESB