Currently not possible due to an incompatibility with the current version of displaytag. 2.1.2u contains improved Unicode support, so this upgrade should be pursued at some point. java.lang.NoSuchMethodError: com.lowagie.text.Table.setDefaultVerticalAlignment(I)V setDefaultVerticalAlignment appears to have been completely removed from iText, and displaytag calls it for both PDF and RTF exports.
More information on this problem: http://www.nabble.com/Release-iText-2.1.0-td16334787.html "This method has been removed as it was deprecated since 2.0.3. The deprecated message mentioned using getDefaultCell() and com.lowagie.text.Cell.setVerticalAlignment(int) instead so it should be pretty easy to adapt the code." Other API changes are documented at: http://brittanysoftware.com/itext/changes/2.0.8-2.1.0/changes.html
And finally, an iText patch: http://jira.codehaus.org/browse/DISPL-450