[TYPO3] RTE and tables problem with borders etc

[wqual]

Hi list,
I successfully imported a css-based template into typo3. Now, I would like to 
add a table using the RTE, but in the Frontend only the text inside the table 
is printed, not the border, backgroundcolor (although visible in RTE of the 
BE).
Is there an extension, template which I have to load into Typo3? I would 
really appreciate any ideas.

Best,
Wolfgang