[RA] How to Remove Crate-Gained Condition After One Specific Weapon Attack

[dxxds0]

I have a unit that acquires a condition when picking up my custom crate. I want this condition to be revoked after the unit uses one of its specific weapons to attack once. How to do this?

Here's the specific situation: I designed an infantry unit that, upon picking up a crate, gains condition P1, which activates another weapon. I want this weapon to be one-time use, so I wrote:

GrantConditionOnAttack:
Condition: !P1

But this can't Remove P1, and it can't specify a particular weapon.

[Mechanicat]

CA mod's dll supports doing this.

it can be probably get done on vanilla too,
using lots of workarounds and whatnot,
however i wont brainstorm it right now.