[Si|ent]

You could make the entire object lift up, or drop into the ground, rather than the barrier arc upwards (as it isnt animated). Might look a little strange though.

p.s. I highly recommend using jernejls SA-MP editor over what you are using currently. There is no need to convert, it's massively feature-rich in comparison and far more efficient for high detail/accurate mapping. Plus of course it supports all of the SA-MP features, such as object removal.