Tigase now supports the full implementation or XEP-0334, See XEP-0334 for protocol details.
This can be customized by setting a list of paths and xmlns to trigger and place storage of offline messages using the following settings in init.properties:
sess-man/plugins-conf/amp/msg-store-offline-paths[s]=/message/received[urn:xmpp:receipts],/message/store-offline
This will require the enabling of AMP plugin, so be sure --sm-plugins=+amp is enabled.