\r\n becomes 
 when generating XHTML (for ePub)

I'm including Windows text files with \r\n end line markers. When I generate
XHTML (for ePub) all lines end with a 
. When I generate HTML no 
is inserted. I don't know if the output is different because the stylesheets
are different or because the tools I use (xsltproc for HTML vs. the ePub
converter which invokes xmllint). 

Anyway the problem is that 
 becomes a question mark in at least one
ePub reader. Does anyone know what to customize to get rid of 
? 

Thanks, 
Boris