Recording Expression Switch Keys

I’m using an old Korg X3 Keyboard, so only has 61 keys and doesn’t have the lower end keys for the Expression Switch Keys on Halion Sonic SE’s 88 note keyboard.

Is there a way to record those expression switch keys without having to ‘connect’ them to the Korg? That would be a great solution! Same with Halion’s Chord Pads.

In Halion’s midi page I’ve managed to transpose my Korg’s keys an octave to the right, leaving 12 actual free keys on the left of the Korg keyboard. Then I’ve mapped Halion’s expression switch keys to its chord pads and can trigger the pads from those 12 free Korg keyboard keys. But that’s a bit of a workaround!
I can’t seem to map the Expression Switch Keys directly to the free keys on the Korg. Or is there a way?

Can I midi control the Expression Switch Keys from an iPad? I’m using a Windows 10 PC.

I’d appreciate any help with this.