We were able to get around this issue with SSL settings for WMQ resource adapter.
By setting system properties in the topmost section of standalone.xml:
<system-properties>
<property name="javax.net.ssl.trustStore" value="/opt/jboss/etc/truststore.jks"/>
<property name="javax.net.ssl.trustStorePassword" value="${truststore_password}"/>
<property name="javax.net.ssl.keyStore" value="/opt/jboss/etc/keystore.jks"/>
<property name="javax.net.ssl.keyStorePassword" value="${truststore_password}"/>
</system-properties>
And specify the ssCipherSuite to be used against our SSL-enabled WMQ Channel in the <connection-definitions> tag under resource adapter settings:
<config-property name="sslCipherSuite">
SSL_RSA_WITH_RC4_128_SHA
</config-property>
Dont know if this fixes your issue, Dmitri, but at least it shows its possible to get around the issue.