Best way to have a single character assist FTL and cast?

I have a team with 3 warlocks, and I'd like to bind 3 separate keys for fear. For example:
Shift+1 -> Warlock 1 assists active window -> Warlock 1 casts fear
Shift+2 -> Warlock 2 assists active window -> Warlock 2 casts fear
Shift+3 -> Warlock 3 assists active window -> Warlock 3 casts fear

I tried a few things, but none of them worked as intended, so I figured I'd just start from the beginning and ask how I should be doing this, rather than experimenting and hacking something together.

For the sake of demonstration, here's what I tried:

I created a named macro in IsBoxer:

Code:

/assist {FTL}
/cast Fear

And set the "Key Combination" in ISB to F12.

When ingame, with a warlock's window active but mapped keys turned off, I can hit F12 (with various modifiers), and it does assist a party member then cast fear. So I think the macro piece is working.

Then in IsBoxer, I created set up a new mapping for this Named Macro so that F12 will activate my assist+fear macro for a specific warlock. But when I press F12 nothing happens. Also tried mapping other keys, with the same result.
Thinking it was maybe an issue with my own macro, I tried changing this mapping to instead activate the built-in macro "/assist {FTL} in Quick Setup 42 WoW Macro Set" (which came with ISB). That didn't work either.
Also tried checking/unchecking the "Slot ID ("FTL") Modifiers from active Slot" checkbox, which seemed to have no effect. Same with Add optional modifiers (those I didn't expect to have any effect, and they didn't).

So I guess I must have some misconception about how this all works. Hoping someone can help me understand where I'm going wrong.

I uploaded my profile here: https://pastebin.com/DdPktJTL

[bob]

These are for when you want to FORCE a specific slot FTL modifier. Essentially when you set these, ISBoxer will send these to the game, so by ticking them, you are sending LEFTSHIFT+RIGHTSHIFT+LEFTCTRL+RIGHTCTRL+LEFTALT+RIGHTALT+F12 to the game. You probably do not have a macro for this combo.


This does what it says, and only sends the modifier for the active slot. This is the option you want ticked. Not the others.


Also, just remember, when changing anything in the Game Helpers section in ISBoxer, you need to do a /reload in game after export (or relaunch the team) before it takes effect.

p.s. F12 is also sometimes a bit of a funny key and doesn't take kindly to modifiers for some people (seems to be language specific). Sometimes it is worth trying with a different key. Because you are using an FTL method in your macro, you will need to make sure your chosen key is not used elsewhere in any keybinds with any combination of modifiers.
You might be better off setting up your mapped key to have two actions, and call the existing /assist {FTL} macro, and then have your /cast Fear as a separate macro, so that way you don't end up with multiple keys that chew through the modifiers with the {FTL} setup.
e.g.