An update on this, for anyone who runs into the problem in the future:

It appears that Windchill did not recognize that the Environmental light was on, and was thus showing a black drawing view. Switching to the Ambient light resulted in the part being shown with it's colors, although the view was darker than desired. This was the reason for using the Environmental light in the first place, because there is a slider that adjusts the brightness. However, there is an 'ambient' slider that can be adjusted when editing an individual appearance that will adjust the ambient brightness of that appearance. Turning up this slider on each of the model appearances resulted in the desired drawing views.

It wasn't Windchill that did not understand the view shading. Windchill and CreoView are only displaying what is stored in the imbedded image. The imbedded image is created when you check a file into Windchill from Creo, if set up properly. To make it work right, you need to set the publishing Creo machine to have the same settings as your work machine in order for the lighting to come through.

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