Dusty is right, don't do it. The stress being fed back would rip it right off.
I don't have access to my tractor to take pictures but FEL's have strong structural members that transfer weight and stress to the frame.
The weight of the FEL is supported by the heavy vertical beams and there are also horozontal beams that will absorb loads to the frame. Like when driving forward and digging or going into a pyle of dirt, the lateral load will transfer to the frame. Without this the FEL could twist aft and brake free possibly striking you.
Here is a link to the people on the other tractor site. I know it's not a Kubota but still the stress from the FEL broke his frame.
If it were me I would do more research on fabricating a kit to adapt it to the frame. There are people on this forum that have fabricated there own FEL's from scratch with purchased plans (blue prints).
Please be safe!
Scott