Question on using setNewGuid() on scoped app

Hi ,

I have a workflow which will create a catalog task , so in the advanced section of the catalog task activity i have  scripted this way :

workflow.scratchpad.sys_id= task.setNewGuidValue();

Dont know why i am getting the sysid as undefined and workflow goes crazy post that.

If i use workflow.scratchpad.sys_id= task.setNewGuidValue(String value); 

it shows me an error in this particular line .

Can someone say how to use this in scoped app.