Normally, ReadyAPI adds multiple security scans automatically when you create a security test.
To add a new security scan to an existing security test:
Open the list of scans.
Click Add Scan.
The Add Scan dialog opens up. Pick a scan you want to add to the security test.
Select the appropriate scan from the drop-down menu and click OK.
The scan will appear at the end of the list.
Click the scan to select it.
Now, configure the scan in the security scan inspector.
The default assertions will be automatically available. To apply other assertions, click Assertions.
With assertions selected, a list of configured assertions is available in the Assertions inspector.
Add assertions as needed.