I'm writing math and I'm using "modern", and I would like to use "doublestroke".

There is an example here, http://www.ntg.nl/pipermail/ntg-context/2008/037124.html, but I think it's not likely to work since families aren't used anymore.

I really can't think how it should be done, and all I've found would be through some substitution mechanism as described in "fonts-mkiv.pdf".

I could use an example of replacing a "vector" of a font, by another font.

There might be things too with "simplefonts" and "fallback" mechanism, but I haven't seen examples with math.

Regards,

Chris