The documentation at
http://plantuml.com/ascii-math is crucially outdated as the provided link to the jlatexmath source
https://dl.dropboxusercontent.com/u/13064071/plantuml-jlatexmath.zip is invalid
I might have found an alternative link from scilab which seems to provide the same jars build from the current version of jlatexmath
https://forge.scilab.org/index.php/p/jlatexmath/downloads/get/jlatexmath-minimal-1.0.3.zip
please comment on this!