Sorry....That's not technically possible.
CSB has an interface that is very much like a word-processor. We can do things in it that are NOT supported by browsers, example use fonts that are not universally available. But the makers of the program wisely choose NOT to give us the option for sideways font.
Browsers have limitations on what and how they can display information. Direction of text is one of those things that causes problems going from browser to browser...
But the good news is that you can workaround this limitation.
Just like when you want to use a non-standard font and still have everyone see YOUR design the way YOU intended, you can make an IMAGE of the text in a sideways vertical alignment and put it at the head of your table.
Take a look at this page about font and images....
The second image example can be done in CSB by adjusting the LINE HEIGHT (space between paragraphs) to tighten the text and centering text in the column but is better done with an image.
