You can also bind it to the carbon fork, with more carbon, or virtually any twine that will allow epoxy to soak in. This is actually stronger than alternatives. But for simplicity sake the carbon fork you currently have would need to have "fender mounts" on it at axle height, or you would have to source a skewer mount rack, which could end up being as much as a fork. If it has zero mounts, that would be another mater. If you want more info, ask more questions here, or look up threads on making bamboo bikes, you will note that the lugs are bound with hemp an epoxy, or carbon. Carbon tow can be sourced for a few bucks on the bay. This kind of thing can be permanent of done over a release for later removal.

You also have a bunch of options on the fork thing. Find a 1 inch threaded fork, they are still out there, and someone may be able to dig it out for you. I tried my favorite shops, but no luck. The Bay had one but not really price competitive. You can also go for a non-threaded fork, just switch you headset and other stuff, better system for this app anyway. Or as others have suggested you could p-clamp any old metal threaded fork, they are still out there. Or you could even get the mounts brazed to one, they only cost about 30 buck for the cheaper forks and a few cents for the mounts, you will wreak the paint but you can't really see the patch under the bags anyway.