There is a documented limitation to virtual entities that although you can add a lookup pointing to a virtual entity the lookups search / filter functionality is ignored so the lookup contains all entites of that type regardless of the searchstring the user might have typed in the lookup box.

Unfortunately this also applies to advanced lookups where you would have extended filter and search functions which simply don't work.

We noticed that this - at least for the simple lookup - is due to the search string not being transmitted to the Custom Virtual Table Provider.

So our idea is simple: Please enable the transmission of the search and filter settings of the lookup to the Custom Virtual Table Provider (which is usually done via the fetchxml sent to the backend).

This would enable us to provide solutions to our customers where they can mix external data sources with the Dataverse source thus providing a possibility to migrate their existing on-premise solutions to the Microsoft-cloud in a step-by-step manner.