How to bind a Template Property to a XML attribute in a custom XML namespace?

I do need to have custom information inside BPMN file, and essentially I use a custom XML namespace for that.
This are some reasons for that, one of which - I do have XSD with the schema definition and documentation.

Now I want to define an Element Template with some properties, which I do need to map to those custom XML attributes (and elements) located in my XML namespace, not “” nor “”.

Is there a way to do that?

Looks like that should work:

“binding”: {
“type”: “property”,
“name”: “myNamespace:class”

But how would I say Modeller to add a namespace to BPMN XML document?
Or how would I create my template for empty BPMN document, so that it would contain the namespace and I could use the snipped above for the property binding?

Hey @rumata
maybe you can have a look here:
In this example it is explained how to add custom properties to the bpmnjs properties panel by creating a moddle extension.
Hope it helps.