Not sure I understand your question correctly. Currently there are two stencil sets available - the Full and Minimal. Full contains all BPMN2 nodes that are understood by the jBPM 5 runtime, the Minimal contains a subset of commonly used ones and is the same as what is available in the Eclipse editor.
We are working on features that will allow you to create custom stencil sets based on the process dictionary terms or other existing business processes. This should be available in the next Designer version. Designer also has now the ability for you to configure custom service nodes or install them from a service repository.
If you are looking to add your own custom nodes and shapes, then you will have to get your hands dirtly and code that.
Hope this helps.