Hello Callens Nico,
To ingest the migrated flow into an existing custom Log Table, you can follow the guidance given on this doc https://github.com/Azure/Azure-Sentinel/blob/master/DataConnectors/microsoft-sentinel-log-analytics-logstash-output-plugin/README.md
In case you are still having challenges with the plug-in please open a support ticket here - https://ms.portal.azure.com/#create/Microsoft.Support As the service type select- "Azure Sentinel"
I hope this helps to answer your question.
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