There is not a way to extract in MRL or in the IBRSD configuration a way to map an event's mc_ueid to a clickable URL.
You can extract the raw data in various formats, but you can't actually provide a link to the actual event programmatically.
This functionality is normally used to forward events from one system to another (eg from TrueSight to Remedy).
From a Remedy ticket, you can't go back to the actual event, you have to navigate to the device and look for events under that device.
What is required:
1. In the DefaultMapping.map file, a means to apply base-64 encoding to convert the mc_ueid to the format expected by the web pages, so that you can display the page.
2. The rest API of the event system should be able to handle either base-64 encoded event ids, or the raw event id
It is computationally expensive to fork/exec a call to an external script to base64 encode the event.