The source code is available as a seperate release from the SSL-Explorer Sourceforge pages.
To install the source code you will need to have Java 5 and Apache ANT installed on the system and configured in the path. Extract the source code from the zip file, once extracted navigate to the SSL-Explorer Installation directory and from the command line run the command ant install. This will launch the Installation Wizard, simply configure the settings and complete the wizard, once complete the Installation Wizard will shutdown. Now run the command ant start or ant console to start the service, to configure SSL-Explorer to run as a service run the command ant install-service.
A more complete guide to installing the source code can be found in the SSL-Explorer Getting Started Guide.