Ray,
In my apps, I have accomplished this by appending the Token to the end of the email body delimited by a string (in my case ### before and ##### after the token). Then when I receive an email, I look for this token and delimeters in the email body. This can be accomplished through a contains xpath statement (for example [contains(Name,'######')] ) or a series of find string functions used in a microflow (find the starting ###, then find the ending ##### and locate your token between those two using substring functions).
Hope that helps,
Mike