Cell width

Hi

I'm adding a Cell containing an Image to a Table object that I'm adding to a header. I wanna know the exact width of the cell, so I can dimension the remaining cells of the row accordingly. I've tried to retrieve  the Cell and Table witdh using the methods Cell.cellWidth(), Table.absWidth() and Table.width(), but  I get  the following values null, "" and 0.0. Is there any way to obtain the percentage occupied by each cell, or this behaviour is part of the same bug causing Table.setWidth() not working properly?

Thanks.