Can I use a different mail client to "Send a Copy" from Pages?

One of my favorite Pages features is its ability to send someone a copy of your document in Pages, Word, PDF, or ePub format via email with only a couple clicks in the "Share" button. But this feature only works if Mail, Apple's email client, is set as the default email client for your Mac. Because I use Unibox as my email client, I'm unable to take advantage of the "Send a Copy" feature in Pages. Is there a work around for this or a settings file within the system I can tweak to allow me to use a mail client other than Apple Mail to "Send a Copy" from Pages? Thank you!