C14N and XSLT

All, 

I am evaluating whether I should make C14N part of an XSLT chain or have something like XMLStarlet at the end of the process. 

I believe that by the book, I can not guarantee an XML serialisation from an XSLT renders a canonical XML, can I? 
To me things like <foo></foo> instead of <foo/> are impossible to force, or did I missed something? 
(I am aware of some undocumented tricks that help me force this in some processors, but that is no guarantee for a long lasting solution) 

I am leaning towards using a C14N dedicated tooling, but the files are big and XSLT streaming would help 

Any thoughts? 

Thanks, 

Geert