Another alternative which I just found is the ditaa version on github, which has SVG support. See https://github.com/stathissideris/ditaa. If you click on the 'release' link on the right, there is the most recent release, which includes a link to a standalone ditaa.jar file.
I've not tried this version, but suspect it will work fine (assuming they use semantic versioning, which indicates the API has not changed).
