Validate an XML file against a DTD file (not against an XSD file)

[silfer1200]

Hello.

Notepad++: v8.8.2
XML Tools: v3.1.1.13

I have an XML file opened in Notepad++ starting with:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE Fonds SYSTEM "sjm.dtd">
<Fonds>

When using: Plugins > XML Tools > Validate now, I get a window asking for an XSD file. But I have no XSD file, because I am using a DTD file, as you can see in the code above.

How can I use a DTD file for DTD validation?

Kind regards.