The easiest way to have a custom service, is copying the WEBGUI service in SICF. This document shows the steps to copy the service and move it to the general "its" path.
Steps to create a custom service
Run transaction code SICF. In the initial screen, inform "WEBGUI" in the Service Name and click in Execute:
Select the node, right click and select "Copy":
Now right click again and select "Paste":
Inform the Object Directory Entry data, according to your regulations:
As you can see, the new "webgui" node is inside the original "webgui". Right click in the new one and "Rename Service":
Set the new name and click in the green ticket button:
Adjust the Object entry:
Now cut the new node:
Confirm the popup:
Select the new destination (/default_host/sap/bc/gui/sap/its) and "Paste":
A new Object Directory Entry adjustment popup appears:
The new service is now available. It is possible to customize the GUI Configuration according to own needs, for example: