http://emonic.sourceforge.net/html/usage.html - Emonic is a C#/.NET 2.0 plugin for Eclipse, the link explains how it's set up.
Finally, after many hours, I got it to work and the (example) plugin works in MB! Eureka!
For possible future users of Emonic (Eclipse):
* U have to install NAnt yourself and set the path in Global preferences (.NET, Building, Nant).
* The "Emonic Auto Builder" never works more than once for me, try making your own builder with the same NAnt path (Project properties, builders, new).
edit: it actually does work, I just didn't know you have to "Clean" your project first (after failures?)
* Sometimes some .build file editing helps overcome some otherwise hidden problems...