First, High Availability Fallback must be licensed.  Below you can see an example of how the Payment Processing Console Workspace Licenses & Privileges page will appear when the license is in place.

Next, configure your primary connection to utilize a fallback connection in the Advanced Configuration tab. Please note that connection names for the same provider type will be hidden from the list.

Now, log in to JDEdwards and set the constant to enable fallback functionality. 

While in JDE, designate and configure a payment instrument to be utilized by the fallback process. The new instrument must be notated using 1SCC in the Special Handling code. 

Finally, in JDE, configure the PQ67SYS1 so that the fallback connection is available for use.