ISBoxer.com

What I would like to do, is press and hold space to launch both flying mounted toons into the air (which is how it is currently set up)
And then when I release space I want it to alt+f or follow. I cant work out how to do it, can anyone help?

There isn't a method to do that. Because jumping is considered a movement command, and like all movement, it requires you to hold the key down in order for it to do more than just instantly press/release the key. All movement is like this.
e.g. if you just tapped the standard WASD keys, the toon would end up behaving like they're having a fit. Same with Jump, just tapping the space bar ends up doing nothing. You have to hold the key down (although jumping is a longer press than other taps, it does not require the length of time that WASD does).

So, because ISBoxer has to follow the "hold" pattern, then it prevents you from differentiating between the pressed and released actions of the key, and thus having a separate action when you let go of the key is not possible.

If you want a follow to occur when you let go of space, your best bet will be to use an addon, like autofollow or EMA (or EMA-C if classic), which has a Follow Strobing option. If you have this enabled, then it will send out a follow command every few seconds.

Okay thanks i'll look into that