The saxon:character-representation attribute
This attribute allows greater control over how non-ASCII characters will be represented on output.
With method="xml", two values are supported: "decimal" and "hex". These control whether numeric character references are output in decimal or hexadecimal when the character is not available in the selected encoding.
With HTML, the value may hold two strings, separated by a semicolon. The first string defines how non-ASCII characters within the character encoding will be represented, the values being "native", "entity", "decimal", or "hex". The second string defines how characters outside the encoding will be represented, the values being "entity", "decimal", or "hex". Here "native" means output the character as itself; "entity" means use a defined entity reference (such as "é") if known; "decimal" and "hex" refer to numeric character references. For example "entity;decimal" (the default) means that with encoding="iso-8859-1", characters in the range 160-255 will be represented using standard HTML entity references, while Unicode characters above 255 will be represented as decimal character references.