If someone is interested, it is also possible to create an event source manually by adding some registry values.
Save the following lines as a .reg file, then import it to registry by double clicking it:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\eventlog\Application\YOUR_EVENT_SOURCE_NAME_GOES_HERE]
"EventMessageFile"="C:\\Windows\\Microsoft.NET\\Framework64\\v4.0.30319\\EventLogMessages.dll"
"TypesSupported"=dword:00000007
This creates an event source named YOUR_EVENT_SOURCE_NAME_GOES_HERE
.