How to set Multiline mode for annotation editbox?

Dear support team,
how do I set the multiline mode for a text annotation?

The class Page.Annotation has a function GetEditType() but no SetEditType(). The documentation states for the return value: "3: MultiLine edit area."

But how do I set that type number 3?

Greetings,
Max

Hi,
i think that Edit Type shall be set in the PDF design phase.
Not in editing mode.
In editing mode, you can just set text.