Does stateless query supports 'IN'

Hi,

I want to make a stateless query in which I should be able to use the 
'IN' syntax.I've wrote a query like this one

   <queryModel name="QUERY_WITH_IN">
      <pattern>
        SELECT * FROM Document WHERE ecm:primaryType = 'Type1' AND 
rgl:category IN ?
        AND ecm:mixinType != 'HiddenInNavigation' AND ecm:isProxy = 1
      </pattern>
      <sortable value="true" defaultSortColumn="dc:modified"
        defaultSortAscending="false" />
      <max>5</max>
    </queryModel>

I have verified that there is a document on my repository that has the 
field 'category' from the schema 'rgl' with one of the values I sent as 
parameters, but no results.
Any suggestion would be great.
Thanks a lot !