DAVENPORT: "vertical" table

[Guillaume Rouchy <rouchyg@gatwick.geco-prakla.slb.com>]

Using the docbook DTD and the CALS tables, I would like to have a column
header instead of a row. I.E. :
+------------+--------+
| Heading 1  | Cell 1 |
+------------+--------+
| Heading 2  | Cell 2 |
+------------+--------+

Instead of having the standard:
+------------+-----------+
| Heading 1  | Heading 2 |
+------------+-----------+
| Cell 1     | Cell 2    |
+------------+-----------+

How can I do this ?

Thanks for the help

Guillaume