[db5] HTML tables vs. CALS tables

Hello,

I have tried using the archives, but didn't (yet?) find the answer to my
question.

DocBook 5 allows both HTML and CALS tables, yet their elements seem to
be in the same namespace. How does one decide at a table element, which
type of table (HTML or CALS) it is? Or can this only be determined by
looking down onto its children?

If the latter, what was the reason for not including e.g. the XHTML
table module into DocBook 5, with the elements being in the HTML namespace?


Best regards
Christian Roth