You can make it happen. If there's a will and you have fab skills or cash you can do this. The rear engine mount hole will need to be drilled to match the swingarm pivot bolt on the bike ur using. Easy. Then You will need to fab a new head mount. That's easy just make it with cardboard first then steel. Then fit up the lower and front mount bolts after you cut the down tube and lower cradle to fit. Aluminum gets weak with welding which either scares people or they don't even know it, but you can take it to a heat treater and they can anneal it to the proper specs and it will be as strong as the frame was originally. That's where most af conversion frame problems occur. Heat treat will cost a little but if you're cutting that important part, just do it. Some cars made with aluminum are actually glued together because they don't want to anneal the complete frame (cost) and without annealing it is too weak.
Not hard, just more difficult and costly than steel. But if you can get the frame free or cheap and u have time to tinker what have you got to lose.
I realize I'm replying late but I just saw this looking for something else. Did u get the frame? Where are you with this?