I manged to create several individual services based on requests found under "Requests to public networks".
Once they are created, a few things became apparent:
1) I can't find a way to list or manage these services anywhere in DynaTrace. There is no way to list, manage or delete them?
2) The only way to see these services is when actual web traffic is collected on them. Only then, they will appear in the "Transactions and services" view. Depending on the external endpoint, it could be days or weeks until anything is collected again.
3) Because of (2), I can only edit and change that service's name and settings once it appears in "Transaction and services".