This is completely conceptual, but what if you designed it similar to this?

add screen SO302000 {
  add container "ShipmentSummary" {
    formActionsToExpand = 1
    add recordAction "SignAndConfirm" {
      displayName = "Sign and Confirm"
      behavior = Custom
      requestConfirmation = true
      action = {
        add recordAction "SignReport" {
          behavior = SignReport
          invisible = true
        }
        add recordAction "ConfirmShipmentAction" {
          behavior = Record
          invisible = true
        }
      }
      postAction = "Refresh"
    }
  }
}

In this hypothetical example:

• We define a new action called SignAndConfirm.
• This action has a custom behavior and will request confirmation from the user before proceeding.
• Within this action, we sequentially add the SignReport and ConfirmShipmentAction actions. Both actions are set to invisible as they should not appear as separate buttons to the user.
• After the SignReport action, the ConfirmShipmentAction will be triggered automatically.
• The postAction is set to Refresh to ensure that the screen is updated after the actions have been performed.

Alternatively, I think a business event triggered by the signature, or whatever criteria you deem would suffice as well, and it wouldn’t limit signers to the mobile app, and could potentially open it up to other touch screen displays or digital signatures in the future.  ;) 

Hope this helps!

-James