Locating custom properties in a iModel

[kardoka]

Greetings,

We are adding custom properties to our IFC model, but once it is uploaded as a iModel, we can not find these properties via ECSQL queries. We have also tried to locate them via the iTwin Viewer, but they do not seem to appear for any element. In the IFC file, these property sets are defined as IFCPROPERTYSET elements.

The properties can be seen using various IFC viewers, like BIMvision (see green property sets in picture below):

Are custom properties preserved once a IFC model is converted to a iModel? If so, can you provide some general advice on how we should extract these properties via ECSQL queries?