you can connect to any JMSprovider from webMethods IS,just copy the Jar files of the JMS provider in the IS/Lib and create the JMSConnectionAlias alias as you normally do in ISAdministrator,with that that connection alias you can connect.Actually i have created JMSConnection for External JMSProviders like TIBCO and iam iam able to connecct.FROM MWS you cannot configure this