It appears i have had some success. After scouring you forums and other posts i have managed to get this to work (it seriously appears as if no one else has managed). I managed to work out that the issue was brought about by Ajaxifying the control. Despite the tab being selected, the onClick event was still not firing.
to select the tab from a value stored in a hidden field, i simply switched out tab.select() for tab.click() and it's working perfectly.