About BPMN extensibility

Hello everyone.

I have doubts about the extensibility of the platform. I am trying to implement an extension of the BPMN model. This means that it is necessary to add new element types (tasks, events, etc.). These new items should appear in the palette alongside the others when modeling. Also, they would have to have their own properties. For example, a new custom human task with new configuration properties.

My question is, is there a way to get this through the extension points (stable or not) of the platform? If necessary to change the source code. What components would be affected?

Thanks.