Now I'm kinda curiuos:

I did setup the CKeditor with my own templates. In these templates the table-cells have classes.
I use these class-names and my modified contentOA.css (containing the css with "background-image=..."),
to present the user with a pretty limited choice of pre-formatted layouts (with actually background images
for cells). This works so far.

Why should our little experiement with html2pdf change that?