HID ActivID 4TRESS AS and Citrix XenApp - Manual (Page 6)

ActivIdentity 4TRESS Authentication Server | Handbook: Configuring Citrix® XenApp™ for Two-Factor Authentication P 6
External Use | May 31, 2012 | © 2012 ActivIdentity
7. In the left panel under Citrix Web Interface, click XenApp Web Sites.
8. Under Site name, select XenApp in the center panel.
9. Right-click, and then double-click Authentication Methods.
10. In the Configure Authentication Methods - XenApp pop-up displayed, select the Explicit option.
11. Click Properties.