Acutally you can export the scene to FBX in order to import in Blender and use Luxrender from there.
The alternative is to hope that the guy behind LuxRenderDS updates it for DS4. Or export your scene to DS3 and use the LuxRenderDS plugin.
However which issues are you having with 3delight?
Often times, when I try and render a scene, it causes Daz to quit. Full renders almost always quit, and recently, even full scene spot renders have been causing quitting issues. Exporting to DS 3 is not an option because I use Genesis figures exclusively in my scenes for all of my human characters.
For the record, I’m running Daz Studio 4.0 Pro on a Mac Mini 1.83 GHz Intel Core Duo with 2 GB 667 MHz RAM and a 64 MB VRAM 32-bit Intel GMA 950 graphics card.