Using SAP XI we can connect SAP system to MQ series. JMS adapter in XI can be used to connect MQ series. Based on requirement, XI to SAP system connections shoul be chosen.
Find the link below
The link talks about sonic MQ but it is relevant for IBM MQ also
We have had good results by using the MQ Series JMS Driver loaded into PI. Here are links to the information you will need to get going...
JMS Adapter FAQ
XI / JMS Powerpoint
Using Content Conversion Module to get MQ Message format in and out of XML.
Using JMS Adapter filter to allow multiple message types per queue
To do it without SAP's integration tool you would rely mainly on IBM's Webshpere integration capabilities. You would probably use IBM's own adapter on the Websphere side to communicate directly to the SAP business system using the methods it knows how to communicate with namely IDOCS or BAPI. I don't know for sure because we went the PI/XI route. You may find more help from a forum hosted by IBM because this forum is not always active.
Websphre Adapter white papaer