On the Download Management screen, enter RC/Query (or any of the other CA DB2 Tools product names) in the 'Search by Product Name....' field. Click on 'CA RC/Query'.
'25 Product Downloads Available' will be displayed for DB2 Administration.
Scroll down and click on 'CA Administration Suite for DB2 for z/OS MSU MVS'.
On the next screen click on 'I agree to the end user license agreement (EULA)'.
You will now be able to order the r20 PAX file:
CA DATABASE MANAGEMENT SOLUTIONS FOR DB2 FOR Z/OS R20 INC00