Htmlvar not present in the modeler

Hi, I wanted to know how to deploy a bpmn from the modeler that contains a mail task that uses the htmlVar.
The modeler does not allow me to use this attribute, but only the normal html. But I need the htmlVar.

Indeed, it was missing. Added it here:

He is not the only one absent. All the variables “*Var” was absent.
But thank you very much for your job.