Well, I dont have Blitz3D no more, but, if I was doing it and the pivot route was a bit of a mare, I'd send the entity to be slingshotted (In this case, the source entity) and check its distance from the destination entity, once it got so close, I'd use the destination entitys position and its distance in a typical Sin/Cos forumla to sweep the source entity around the destination entity.
You can check how far its gone round, and after its performed a semi-circle sweep, unclip it from the Sin/Cos routine and send it on its merry way! :)
You can check how far its gone round, and after its performed a semi-circle sweep, unclip it from the Sin/Cos routine and send it on its merry way! :)