multi signature – Is it potential to make use of Electrum to create a multisig pockets with a trezor and an airgapped coldcard?

I arrange a 2-of-3 multisig utilizing Electrum, a Trezor, and a Coldcard. Throughout testing, I bumped into points utilizing the Coldcard to signal.

My method:

1. (On Electrum) File -> New/Restore -> Multi-signature pockets -> Use a {hardware} gadget
2. Plug in Trezor, unlock, and arrange as p2wsh.
3. Repeat steps 1 and a couple of for second Trezor.
4. Plug MicroSD card into Coldcard.
5. (On Coldcard) Settings -> Multisig Wallets -> Export XPUB
6. Plug MicroSD card into pc operating Electrum.
7. (On Electrum) Enter cosigner key
8. Paste p2wsh xpub from MicroSD card into textual content field.

This labored and my pockets was arrange. I despatched a small quantity of bitcoin into it to check that I may signal transactions with Electrum. I used to be anticipating the UX to be much like that of a singlesig airgapped Coldcard used with Electrum, which means I might create a transaction and click on the “Export PSBT” button. Deliver that to my Coldcard and signal the transaction. Nevertheless, the transaction popup solely has an “Export” button and no “Export PSBT” button. The “Export” button provides me a .txn file that’s json containing the tx hex. Coldcard doesn’t acknowledge this file and due to this fact can not signal it. I used to be capable of finding these docs, particularly the part titled “Air-Gapped Creation of a Multisig Pockets”. Nevertheless, these docs appear particular to Coldcard-only multisig setups.

Is it potential to export multisig PSBTs from Electrum for signing on an airgapped Coldcard or is that this one thing that’s merely not at present supported? If it is supported, what do I must do?