I've updated some pages in the
developer documentation and add this
page that gives some instructions on how to build and package plugins.
At the moment, there is only one plugin available:
weasis-isowriter, to burn iso image with selected DICOMs and optionally included the JPEG images and the viewer. This is an "Export Dicom" plugin type. And the project
weasis-plugins-war-builder is a simple example on how to build weasis-ext.war (extension of weasis.war containing plugins).
In the master branch of Weasis, there is a root directory called "archetype" which contains Maven archetypes for building plugin's skeletons. For now, there is only one for building a sample with a toolbar and a right panel tool for the DICOM viewer.
Sorry, I don't really understand what you want to achieve, because Weasis is already a single instance application (except for the portable version on Mac and Linux).