File>Save as>Deprecated gives access to the old script-based presets (.dsa etc.) but not to .dsf.
So, Richard, what do you think the best way to submit the product is? Will I get a lot of complaints about only being compatible in DS 4.5 and up? Or do .dufs work in 4.0? I'm corn-fused... When I think about it, most of the stuff I've bought only contains the duf files.