Applying entities in included XSLT documents causes error

[mhme]

I have an XSL stylesheet with entity definition in it:\[code\]<!DOCTYPE xsl:stylesheet SYSTEM "entities.dtd">\[/code\]entities.dtd contains only one definition:\[code\]<!ENTITY copy "©">\[/code\]If I use &copy; in the document having the DOCTYPE declaration, everything works fine. But when I include another XSL document and try use the entity there, XSLT-processor says that 'copy' entity is not defined.How can I define a global DTD to use it in any included XSL stylesheet?