Adding jcr:mixinTypes="mix:referenciable" to document view xml

[Edgar Merino]

Hello,

  I'm trying to add the jcr property jcr:mixinTypes to a document view 
XML, however it always fails with the following exception:

  The prefix "jcr" for attribute "jcr:mixinTypes" associated with an 
element type "blogEntry" is not bound.: The prefix "jcr" for attribute 
"jcr:mixinTypes" associated with an element type "blogEntry" is not bound.


This is an example of an xml I'm trying to import with this:

<blogEntry someAttribute="ss" jcr:mixinTypes="mix:referenceable">
  <comment title=""/>
</blogEntry>

What am I doing wrong? thank you,

Regards
Edgar Merino