Make Ajax4JSF work with accents

When using ajax4jsf to refresh parts of the interface that contain non-ascii characters, nothing happens.
There are parsing errors in the XML received from the server (Error parsing XML).
Comparing to an older version that works, now non-ascii chars are sent as HTML entities (é) whereas they used to be sent as UTF-8 characteres.
There also was an upgrade from ajax4jsf-1.1.0.jar to ajax4jsf-1.1.1.jar which may be the culprit.