Evaluating expression of Facelets components in Richfaces sort

I have some problem evaluating expression in a Facelets component defined in a .taglib.xml

SortField2.getExpression() 

gives me the value "#{sortBy}" instead of evaluating the value.

My component (a simple column) is defined as:

  <ui:composition>
      <rich:column sortBy="#{sortBy}" width=开发者_JS百科"#{width}" styleClass="#{styleClass}">
          <f:facet name="header">#{header}</f:facet>
          <ui:insert />
      </rich:column>
  </ui:composition>

I see that in TagValueExpression there is a "original" field which contains my value, but unfortunately it is private.

Any idea on how to extract it?

Also posted on Richfaces Forum

Thank you for your help.

You may be able to get "sortExpression" to work, instead of using "sortBy".

Also, instead of #{sortBy}, would ${sortBy} do any good? (A long shot)