Funny I just tried this, and decided to search to see if anyone else had this same issue, or if I was doing something wrong. I haven't tried adding grapple to the Titan armor, however I've just recently tried to add it to the Psi armor with the same results as above. I tried adding in the eAbility_Grapple when the normal method failed, but then I started to shoot to grapple, which also resulted in my soldier getting stuck in mid air I have however been able to add the Ghost ability to Psi armor without issues And I've been able to add the Grapple skill to the Ghost armor properly So I'm unsure why the Psi armor won't accept it, and apparently the Titan armor wont either, however the Ghost armor works perfectly fine with it.