I suspect once the Pak is loaded you will just need to determine the path to the asset and use a soft reference to get it. I’d recommend you check out my colleagues post here.
Quote:
The AssetRegistry only knows about the assets that were present at cook time. It loads this cached information during startup from the serialized version of the AssetRegistry (AssetRegistry.bin) which is stored inside pak files.
Unreal will load a number of AssetRegistry.bin files during startup, for example the AssetRegistry for each plugin is loaded on startup, if it is present.
Additionally the AssetRegistry listens to the FPackageName::OnContentPathMounted delegate, so when a new mount point is mounted the Asset Registry will start to asynchronously search the new directories for any assets and add them to the internal database.
This will be asynchronous and the asset might not be available immediately.
IAssetRegistry::ScanPathsSynchronous can be used to force an immediate update of the asset cache and make new assets available through the asset registry in the same frame.
Hope that helps you take the next steps.