We normally just run SET for these types of engagements.  If you can base your template off of one of their existing internal emails that is your best option.  Back-up plan, make it more of a generic announcement ("Please update your employee benefit options."), and when you construct the email and phishing web page go to the targets home webpage and mimic their font, color schemes, logos, etc. 

@ladynikon: You can contribute just by asking good questions!  I mean if you can't find your answer by quickly search the site, it probably means that others would like to know the answer. So starting good threads are a great way to contribute when you are new.

So, welcome aboard!

Go to YouTube and search for eLearnSecurity - Malware Analysis. There's 2 good videos there as well, pretty basic, but cool