New mail message in default mail app

I am using Mailbox app for mail. I can not replicate a global keyboard shortcut with Keyboard Maestro. I was going to give up on the idea but saw that when I click a “mail link” (share sheet) or a mailto in a browser, it opens a new message just fine.

I was wondering if there is a applescript I could use to open a new message in the default mail app. Mailbox has no applescript support directly from what I can see.

Thanks!

The open location command addresses your default application for the relevant protocol. So;

open location "mailto:someone@example.com?subject=This%20is%20the%20subject&body=This%20is%20the%20body"

Perfect, works like a charm. Thanks Shane!