If you mean rockets from other plane, then if you are in range to fire regular rockets at them (even by lobbing them) you are already very close to get HARM through anyway, possible even close enough to make a run into minimal range zone. But I think SA-10 wouldn't target them anyway
It perhaps could be done with MLRS. if the SA-10 will target the rockets then you can easily oversaturate it with just two MLRS units. If not then MLRS will sooner or later hit it. (question then is if SA-10 would be placed close enough to frontline to be within MLRS range in real life scenario, but then again this is game so who cares)
edit: I just realized that you probably meant firing rockets into the void, not targetting anything. Just put them out there to be targeted by SA-10.