Generate mail in kmail with cli

Hi!

I started using kmail as my mail client. And I want to generate mails from my CRM with preset mail content as HTML mail.

I found kmail --html parameter. Which should generate an HTML mail . But it does not.

When I call
kmail --html "<strong>Text</strong>"

the composer window opens and hast
<strong>Text</strong>

in the content and not as expected Text.

Is this a bug or do I have to change the call?

Jan