How do I create a batch system that uses plugin with MEF ?

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C#

.NET

plugin

.NET4

MEF

I need to create a system to execute some scheduled jobs.
I considered it's a job for MEF.
The idea is to have a central blok where I can attach some other components in the form of MEF plugins.
For example I would like to have a class for data source, a class for data destination and a class for transformation rule.
I need to specific wich concrete class (derived from base class) I would like to use in terms of source, destination and transformation.
During the runtime the engine must read data from sources, pass data to the transformation class and write the otput with the data source for the destination.

wich use the best OOD Pattern for this problem ?
Do you know where I can find some example code or tutorial ?

Regards
Maurizio