Add a weapon to a Character and creating animations for it with a Control Rig

I’ve currently made some animations by attaching the weapon to the control rig in the sequencer.
Although now, as you say, i’ve noticed that it is different from having it attached on the SKM itself since the animations i’ve created don’t match with the equipped weapon when i play them on the character, because it doesn’t apply the transforms i’ve made to the weapon in the sequencer to the weapon on the character itself.
How can i attach the weapon to the character itself and control it with a control rig to animate it too in the sequencer?