Hi Bruno,
1] Can you provide an error message regarding the admon graphics?
Can you peek inside your FO file to see what attributes the
fo:external-graphic element in an admon has? Does the path shown there
lead to the image file on your system (relative to the FO file)?
Regarding RNG validation, the howto.xml file is valid with respect to
DocBook 5b9, according to Oxygen's RNG validation. I have not been able
to validate the howto.xml file with xmllint. It reports errors that are
not there in the file or the schema.
2] It looks like you expect FOP to natively process MathML, but I don't
think it has that capability. Most people convert their MathML to a vector
graphic like SVG and use a mediaobject to reference it.
Bob Stayton
Sagehill Enterprises
DocBook Consulting
bobs@sagehill.net