cell factory defined in FXML leads to ClassNotFoundException

I've been having difficulty importing custom components into Scene Builder. I've made a custom component which consists of a table as well as a defined cellFactory.

See

http://stackoverflow.com/questions/24016229/cant-import-custom-components-with-custom-cell-factories

for code complete issue. If I have <cellFactory> tag with <TestFactory> I am unable to import my custom component due to a ClassNotFoundException. However, if I comment out the <cellFactory> tag, I am able to import the custom component into scene builder.