[TYPO3] RTE should not use the align-attribut for p-tags; how can I change that? XHTML-compliance wanted

[Christopher]

Hello together,

I nearly have the RTE configured to do what I want it to, but there is one 
point I still don't like:

I adjust text using the buttons left, center and right.
The result is the following code which is not XHTML Strict-compliant, 
because there is no attribut "align":
<p align="right">text</p>

I would like to get the following:
<p style="text-align:right">text</p>

How can I manage to get this result instead?

Christopher