Here a some quick tips on how to build the .deb for a plugin. Probably lots of ways to do this but this is what I did to make a new cups .deb as an example.
1. Install the needed packages
2. Get the source
Code
wget http://packages.omv-plugins.org/pool/main/o/openmediavault-cups/openmediavault-cups_0.4-6~1.gbp368731.tar.gz
3. Extract the source
4. Create the .deb