Trang and XSD annotations

Hi,

After many years using XSD i decided to give RelaxNG a try. I really like the compact  syntax but i cannot convert comments into XSD annotation using Trang. I noticed that if I mark a comment with ## it's transformed into an RNG annotation but it doesn't work for  xml schemas.
Does anybody know how to solve this problem?

Alternatevely, is there any tool like http://titanium.dstc.edu.au/xml/xs3p/ to generate docs out of  a RelaxNG  schema ?

Thanks

Alessandro