I'm also using Open Office (now Libre Office) for documents but I have no experience with formatting .ods docs from .NET. As I know there are commercial dlls for exporting spreadsheets but we cannot use them in open source.
In that connection, please excuse me for my absence these days. I'm working hard now on next general release of FSB. It will allow easy and dynamically loading modules. It will be much easier to expand FSB without touching the core application. I'll provide some kind of interface for importing and exporting data, so it will be very easy to add functionality to the program with dropping a module in the program's folder.
I'll made an overview of my goals soon.