I use SAOtng for image reduction. SAOtng should be able to display images in grayscale. It cannot. However, using alternative windows managers (i.e. other than enlightenment) SAOtng works fine. It is important to be able to display astronomical images in grayscale to bring out all the detail. Also, SAOtng works fine with KDC and Afterstep. As an aside, I cannot find my bug report from last night, but I have determined that there is a problem with Xconfigurator in using a NEC Multisync XV17+ monitor. The Xconfigurator program does not respond correctly via menu selection or probe for its capabilities in the "Capable of displaying ... at xx Hz" query. When I select a custom monitor and capable of displaying 1K X 768 (?) at 60 Hz, I can get that resolution in 8 bit modes. With the routines defaults for the monitor, I cannot get that resolution, and Xconfigurator hangs the system on backing out.
This isn't really the fault of anything besides your use of an 8-bit display. enlightenment is probably eating most of the colormap for itself. I'm not familiar with SAOtng - if it can do private colormaps, that would allow doing what you want. This bug is so old that I'm guessing you have a new video card by now :)