Concordion: How get the parameter value inside #TEXT

I am using Concordion to test some java components. I will write something like

  <pre concordion:execute="someFunction(#TEXT, #a)">
   { 
    id:123,
    name:<span concordion:echo="#b"/>
   }  
  </pre>   

I want to value of #b is calculated and substituted dynamically. But instead of value #b in someFunction comes an empty string. Similarly, if use

name:<span concordion:execute="getBValue()"/>

If someone has done something like this, could you please help.

Thanks.