TinyMCE/HtmlEditorConfig: enablePlugins('template') not working ("No templates defined.')

<%- if @topic_view.topic.tags.present? %>
<%= t 'js.tagging.tags' %>: <%- @topic_view.topic.tags.each do |t| %> <%= t %> <%- end %>
<% end %>

Silverstripe Version:4.4

Question:
I’m trying to enable the template plugin for TinyMCE as it was described here:
https://www.silverstripe.org/community/forums/customising-the-cms/show/23046
The icon shows up, but i cannot get the created template

app/_config.php:

HtmlEditorConfig::get('cms')->enablePlugins('template');
HtmlEditorConfig::get('cms')->insertButtonsAfter('underline', 'template');
//Specify location of your snippets//
HtmlEditorConfig::get('cms')->setOptions(array('template_templates'=>array(
	array('title'=>'Name','src'=>'public/htmlsnippets/name.html','Name'=>'Name')
)));

Did anyone get this running?

Thanks in advance and best regards
boo