In reply to DSIG table -- looking for clarifications:
That's a general comment about DSIGs, David, regardless of format.
The issue for Windows in determining what constitutes an OpenType font, as distinct from a TrueType font, inititally for cosmetic purposes (icon presentation) and legal purposes (trademark), was confused by the fact that all the OpenType Layout tables are optional, and all the common sfnt tables needed to be backwards compatible. So Microsoft decided to define a TTF-flavour OpenType font as an sfnt with a OT DSIG table. It's an odd decision that has confused people ever since, including, apparently, the Word 2010 programmers.
