Hi Nickj,
DW CS4 does still offer alignment for table cells, rows and columns.
If you select the cell or column (click the <td> in the element info bar at the bottom), and the 'CSS' icon just below in the Properties Panel it will give you the option to align how you like.
When the 'new css rule' box opens up, select 'class (can apply etc)' from the options drop-down, call it something like 'cell_align_left', and have the class css placed on your page or in your stylesheet.
Having said that, from your code, I don't see why this should be necessary.