[NTG-context] Symbola font glyph size

Hello, I have some troubles using the Symbola font mentioned some time ago on the mailing list (http://users.teilar.gr/~g1951d/Symbola602.zip). It seems like the font metrics are loaded correctly, but the glyphs in the pdf appear approximately half the size, leaving white space above and next to it. Here is a minimal example: \starttext Gg {\definedfont[file:Symbola602.otf]Gg} Gg \stoptext If I use \definedfont[file:Symbola602.otf sa 2], the glyphs are more or less the good size, but the metrics are way too large. I have no problems with this font in OpenOffice. Any ideas? Vianney