JGloss is open source software. You can grab the source code and enhance it yourself. All you need is knowledge of the Java programming language and a few tools.
Current state of the JGloss continuous integration build at Travis CI:
JGloss uses XSLT style sheets to convert the JGloss document to the various export formats. Currently, the only way to add new export formats is to modify the source code and building it yourself. If you want to want to have a go at it, get the source code and look in jgloss/src/main/resources/export. export-descriptor.dtd contains some documentation regarding the export format. Add your new export descriptor to the list in jgloss-core/src/main/resources/messages.properties under the key exporters.