Authorised email addresses

I am about to go on an expedition ship to Antarctica and want to post to my blog using Postie. The ship provides email access through their satellite communication system but no direct access to the Internet. I will not know my shipboard email address until I am on board and therefore cannot adjust Postie’s settings to include it. Therefore I cannot ‘pre-authorise’ Postie to use it.

Is there a workaround that will let me post as admin post from an unauthorised email address that doesn’t compromise the security of my web site ( e.g. Allowing anyone to post)

Thanks.

http://wordpress.org/extend/plugins/postie/