Hi Jeff,
We actually have added a field for Preheader text in our latest release. If you update your ClickDimensions version you'll get that feature and you won't have to code it and it will show up nicely in the inbox. Here's the information about the newest release: http://help.clickdimensions.com/new-release-july-2015/. Here's how to update: http://help.clickdimensions.com/automatic-updates-to-clickdimensions/.