This list is accessible from the Provider No. field in any Provider's configuration screen.
File > Providers > click the selector button alongside the Provider No. field:
NOTE: From EXACT v12.11 there are new columns in the View HICAPS Providers window: Terminal ID and Merchant ID.
IMPORTANT: The displayed list is valid only from the last terminal synchronisation. You need to manually synchronise to view a current list.
To manually synchronise the terminal and update / refresh the View HICAPS Providers List
In the View HICAPS Providers window, click the Provider Synch button, as shown in the above image.