SDF collision object

[jost0]

Hi,
I am trying to create a rather simple scene with a signed distance field-object and a regular plane in C++.
I have generated the signed distance field using Discregrid and now want to insert them into a scene.

Q1: How do I load the files properly for bullet to recognize these as SDFs?
I have been looking through loadURDF() which uses the prefix of the loaded file, but I'm not certain this is the route to go..

Any help is much appreciated