Aim at Minecraft flans mod?

I installed the Flans mod in Minecraft. When I go into F5 mode so that I can see my figure from the outside, he always holds his guns down and never aims through the rear sight.

See pictures, the top is how it is with me, the bottom as it should be

How do I change that, thanks in advance!

Aiming is only possible in the first person perspective.

I don't mean that, there are a lot of reviews on Youtube, where they also go into F5 mode and then it targets like picture two.