java - Accessing BIRT Elements from script

Question

I have BIRT Text element in Master page: eg: elementID : 175 element name :myElement

also I have a PI chart: and once I click on its categories I want to invoke a script and write some text to the "TEXT" element. I tried as below: but both didn't work

  reportContext.getDesignHandle().getElementByID(175).text = "some text" 

  reportContext.getDesignHandle().findElement("myElement").text = "some text"

Appreciate your help on this