You probably are mostly interested in default.properties, which will allow you to change how spark behaves… spark.properteis handles other things such as the image names, etc.
Note that there is another “spark.properties” file that gets created in your %APPDATA%/Spark directory when you first run Spark after it’s isntalled… that one holds various settings such as servername, etc, and get’s over-written during spark’s runtime (so your changes will get replaced!). That file is not the same one that’s in the spark source code.
the default.properties file gets built into the spark.jar file when it’s compiled. i do not know of a way to modify that file without needing to re-compile spark from source. you basically are making your own custom spark at this point.
it’s not hard, there are many guides on the forums how to compile spark, and even guides for how to create an exe or msi installer file.
Start by grabbing Spark’s source code from github: https://github.com/igniterealtime/Spark
There’s a “Download Zip” button in the bottom right corner if you don’t know how to use git to clone the repo.
From here, you will need to make your changes to the default.properties file to suit your needs. It’s located at: src/java/org/jivesoftware/resource/default.properties
Then, follow one of the guides to compile spark. There’s the one you posted earlier:
http://community.igniterealtime.org/docs/DOC-1521 (it’s a little old now, but should give you the general idea)
This guide is more about creating a custom Spark: http://community.igniterealtime.org/message/225739#225739
It’s also a little old now, but the largest difference is Spark is now hosted using Git on Github, not on SVN anymore. If you downloaded the zip of the source above, just skip the downloading steps. Also skip the Openfire steps since you are only after customizing Spark.
This opens the door to customize a bit more. You can add your own images to brand it for your company, etc. It may take a little trial-n-error, but the end result is definitely worth it.