Not able to reference the Test with a Datapool in

问题:

Tool Used: IBM Mobilefirst Platform Test Workbench 8.7 (Free Version)
OS: Windows 7

Problem Description:
1) Have created a Test case in Test Workbench in Record mode. (For a Login Scenario)
2) Inserted a new Datapool and have added values to Username column in the Datapool.
3) The Test script must refer the datapool and substitute the values from Datapool Username column into the Username field in the Test script.
4) Have followed the procedure outlined here.
(http://www-01.ibm.com/support/knowledgecenter/SS2HS7_8.7.0/com.ibm.rational.test.lt.moeb.tutorial.doc/topics/ios_lesson7.html)
5) Getting stuck in Step 6.b. I right click on Username field in test script and select Substitute and get an option Select Data Source
6) The Select Data Source option is disabled.

Is this because i am using a free version and not a licensed version of IBM Mobilefirst Platform Test Workbench 8.7 ?