Weights from LibSVM
Having had exellent support from Marius I thought I should share some conclusions.
LibSVM does not provide the weights as output, but only as part of the model. In case we would like to use the weights (quite common) then WeightBySVM does not give us the LibSVM weights but the JMySVMLearner version. The solution is to use WriteasText on the LibSVM model outputs and then Filter and GuessTypes to 'clean' and recast the SVM model data into and ExampleSet of weights which can then be used.