Ok some updates after a bit of an absence. By setting the Presets setting to BULB, on the Indi Main Control tab in Kstars, I am able to take 60s, 120s or 300s exposures in an automated sequence. Indi will thro a failed to expose error, then go thru the motions of taking another image (but not actually doing so) and the exposure will complete. The downside is that the total time for the image capture is effectively double your requested exposure time. But hey, long exposures are now possible!