Hey there, Ryan!
However, for now, there are a couple of options that might be helpful. If you want to continue to use the plugin, you could add some "pre-filled" text in that field by adding a predefined value for your list:
How do I set default merge values (like Dear Customer)?: http://eepurl.com/hcDC
So, for example, you could use "mm/dd/yyyy" as the predefined text for that area so that your subscribers know exactly how to format their date field. Here's generally how it will look in the form:
Screenshot -- http://cl.ly/3F2Y0V1B3746180B021Z
Or, if you want to get a little fancier, you can also use a slightly more intensive method, laid out in this post:
How can I add my signup form on my website?: http://eepurl.com/gOGN
And of course, if we can help with anything else, give us a shout. We're happy to help!