Georeference ECW from values in a TAB.

Hi, I am trying to georeference some ECW files. I have TAB files which contain ground coordinates of the ECW extents and I've been able to extract these using attribute expose, filter and string extractors. What I now need to do is get these values associated with the min and max extents of the ECW but i'm not sure how to approach this. The Rastergeoreferencer and Raterextents coercer looked promising but neither have the option to apply the coordinates ti the ECWfile. I wondered if featuremerger might help but not entirely sure it would. Any guidance/assistance/advice anyone has about this would be gratefully received. Thanks in advance, Jake