cropping .sid ortho imagery files in GM?

Hi all,
Is it possible to edit .sid files in Global Mapper? I have several .sid files with black chunks i need croppoed out, but I dont want to lose the geospatial referencing by exporting and editing .tif files. So it a nutshell, is there some way to 'mask off' the black areas in these .sid files?
Thanks!
G
Is it possible to edit .sid files in Global Mapper? I have several .sid files with black chunks i need croppoed out, but I dont want to lose the geospatial referencing by exporting and editing .tif files. So it a nutshell, is there some way to 'mask off' the black areas in these .sid files?
Thanks!
G
Comments
Let me know if I can be of further assistance.
Thanks,
Mike
Global Mapper Guru
gmsupport@bluemarblegeo.com
http://www.globalmapper.com