The rope around the cow works great, BUT, if tight enough for not to be able to kick - she also cannot lift her legs to walk. It would have to be loosened after each feeding.
If you have been working with her for 3 WEEKS and she has not accepted this calf, it doesn't sound good.
Try keeping a dog in the pen next to her. May make her more LOVING towards her adopted calf.
Can you tie her with a halter - not in the chute?
If so, tie her up, put the rope on her cinched up tight (be sure to use a slip knot) when the calf is sucking - loosen the rope a little - than if she's not kicking - loosen it some more, until there is NO pressure. Don't be afraid to POKE her if she kicks. Let her know that behavior is not acceptable.
Have to hand it to you, 3 weeks is long time to mess with her!!!