How can I add OVF properties?

Hello,

I am trying to add some new OVF properties to a particular machine.

After going through the API programming guide I come to the conclusion that I shoud use the ProductSection. However I couldn't figure out how to actually add a new ProductSection (when for e.g. myVm.getProductSections() return an empty list). I'm also not sure how to add additional properties to a ProductSection. Can someone provide me an example on how to do this? I'm using Java SDK.

Thanks