Nested tables and borders in Writer/Web

[FTAJ]

Hello
I am facing a strange problem of "silent rewrite" of the HTML code, which leads to important layout loss.
Imagine (or even better: create a new web document ) a page which contains a big table with 0-width borders, with multiple rows and columns. In one cell, I add a new table (=>nested) with coloured borders. I save the document, everything is fine if I open it with a navigator.
The problem is, when I open the HTML page again in OO, the display is strangely altered. In fact, I can see, when saving the document again, that the nested table has been silently incorporated to the parent table, whole cellspacing has changed, and of course my coloured borders are gone. As far as I can see, this is done when opening the document.
Is there a way to force OO not to modify the HTML when opening it, or at least not to rewrite nested tables ? If not, is there a simple way (no source code editing because my users do not know HTML) to modify the display of a specific cell's border ?
Any help or advice very welcomed !
Thanks in advance, best regards
FT

[ms777]

have a look at http://qa.openoffice.org/issues/show_bug.cgi?id=38961 (and vote for it)

[FTAJ]

Thanks for your answer, even if this is a very bad new for us !