1. open/edit(create) with Notepad **\Clients\webserver\settings.bin
2. and add/save as last line
3. restart HTML5 via AdmintTool GUI
4. now in **\Clients\webserver\web_log.txt you should see following message Enabled HSTS HTTPS header! indicating that the HSTS was activated.
As in notation above remember, after activating HSTS you won’t be able anymore to access http links from your page.