Global Mapper v25.0

Saving g4 MrSID out of Global Mapper 22.0

I am having issues getting the background alpha layer to get processed out as band(5) alpha transparency layer when exporting a g4 MrSID from a 4band geotiff.  It works fine when saving it out as a 3band MrSID but does not turn the background transparent when trying to export as a 4band MrSID image.  It works fine in Geoexpress (Extensis), but I needed to geographically shift the dataset in GM 22 and then re-process it back out as a 4band MrSID mosaic with a transparent background.  It keeps making the background the color of the physical color of the background in GM instead of making it transparent... doesn't matter if it's 255, 255, 255 or 0,0,0.  I feel like I have tried everything.