Sorry mate, editing the t-log is not possible (thanks god). My usual way of fixing such a situation would be make a t-log backup and do restore with stopat just before the errondous update. Since this is not possible you might wanna try LUMIGENT Logexplorer(ww.lumigent.com), but I must tell the option "undo user transaction" is not functional in the trial version.
[font="Verdana"]Markus Bohse[/font]