Probably a question for the Autotask community but seeing as though i am an Autotask user i thought i'd reply.
I don't think it can be done (yet anyway?) You need to set up Automatic work flow policies in autotask.We do this for exactly what you are talking about but we don't charge for it - it is "Part of what the customer pays monthly for"
See the screenshot for an example of a Work Flow rule.
Check out the Autotask Community, i may have missed the point because i don't know what you are talking about the EMAIL XML thing.