As the NTRS is still off-line, I've had to broaden my searches for technical information. Google and Bing are next to useless to get any high detailed drawings. Sometimes I get a good close up photograph of a part, but the resolution is mostly poor, mostly.
However, from a series of photographs available on the Kennedy Space Center Media Archive I did manage to get good photographs of the External Tank, Umbilical Doors, the Orbiters in Processing, etc. So, for the time being, I have completed the modelling of umbilical and 'pipework' between the External Tank and Orbiter.