Query Related to catalog task fields in workflow

Hi,

Actually i am trying to auto populate the configuration item & assignment group value in the task by using the workflow. while trying to set the values for the configuration item through script we are facing some issue. i can able to set the values for the assignment group by task variable

code

Assignment Group set value

task.assignment_group= "64cec6b34a36232b01d80299d4fc806b";

task.request_item.configuration_item = "a27d92640a0a3c4a00452fdbf671f650";

Configuration item is not displaying ....

Thanks
Senthil.R