Adding pin constraint to particle in runtime.

[aaamarkin]

Hi.
I have existing rope with couple on handlers on both of rope ends (attached to first and last rope particle).
I want to substitute them (or possibly only one of them with pin constraint).
I think handle can be removed/added with the help of disabling/enabling handle gameObject.
For adding ping constraint I'm launching some variations of following coroutine:

Code:

private IEnumerator AttachHook(){
        yield return 0;

        // Pin both ends of the rope (this enables two-way interaction between character and rope):
        ObiPinConstraints pinConstraints = obiRope.GetComponent<ObiPinConstraints>();
        ObiPinConstraintBatch pinBatch = pinConstraints.GetBatches()[0] as ObiPinConstraintBatch;

        // remove the constraints from the solver, because we cannot modify the constraints list while the solver is using it.
//        pinConstraints.RemoveFromSolver(null);
        
        // remove the first constraint.
//        pinBatch.RemoveConstraint(0);
        
        pinBatch.AddConstraint(obiRope.particleIndices[_obiParticleHandle.FirstParticleIndex], obiColliderToAttach, obiOffsetToAttach, 0);
        
        // Add the rope to the solver to begin the simulation:
        pinConstraints.AddToSolver(null);
//        pinConstraints.PushDataToSolver();
        
    }    

I was experimenting with Adding/Removing from solver and with pushing data back to solver without success.
I can see generated with script pin constraint in unity inspector, but it does nothing.
What am I missing?
Should I reinitialize rope somehow?

Thanks a lot.