Hi @daniell welcome on the plugincafe forum,

Don't worry since it's your first post, I've set up it correctly but please for the next one, make sure to read and apply the next rules:

Q&A New Functionality. How to Post Questions especially tagging.

Finally, regarding your issue, you may find relevant the NodeData::GetDParameter() Manual and NodeData::SetDParameter() Manual.

Cheers,
Maxime.