Looks like other grouped segments work fine, like AM and GAME A/B. But just to be certain, try making a dummy ungrouped segment using the same id as the one for the colon to see if it shows up. It's also possible you simply have the wrong pin number. Which SM510 pin lights the colon segment? And of course, can't rule out an emulation problem either.
Is this SVG final? What I always do before potracing the scan to SVG, is clean up any dust particles, scratches, wear&tear. This way it won't look rough around the edges.
