I have the same issue.
On the SNIP_EmailTemplate_NewEdit snippet, you can manually add a new tab for "HTML Source"
And then have a text area that is set to the "Content" attribute of your template. This will allow you to put in your souce html. Tokens will still work as expected.
The simple rich text editor provided by default strips formatting for itself to work, so if you don't need that functionality, I'd remove its tab entirely so it doesn't accidentally format over your data again.
It's a change in the module, so just be concious that if you update the module you will need to re add this functionality.
Hi Thomas Urech
Haa! I can give a approach
1.Create an entity e.g., MyModule.EmailTemplateFile (generalize from System.FileDocument).
2.Build an admin page to upload the .html file (no editing inside Mendix).
3.At send time:
CommunityCommons.StringFromFile or CommunityCommons.StringFromFileDocument (depending on your version).
I hope this helps!!