If this is currently a feature, I don't know how to do it.
What I'd like to do is to have a message code that inserts a formatted date, but one that lies in the future of the mailing, such as:
"in 3 days, on !futuredate+3" which would be translated to
"in 3 days, on Monday, July 26th".
I realize that this may be difficult to implement, but it would really be a great feature to have.