DOCBOOK: centering images

Hello,

I have following line in my article. I use double column layout.
Centering in this case does not work correctly. It renders image in
between columns (if image was originally in 1st column) or it centers
image on right margin (if it was in 2nd column originally).

I use DSSSL stylesheet and openjade.

<imagedata entityref="closenesstime" align="center"/></imageobject>

Radek