This is something that I was quite surprised that wasn't supported out of the tin with SSRS. When you schedule an email delivery, the report is always sent as an attachment. What would be great, if when you specified the render format as "MHTML"...
Within SSRS, or at least Report Builder 2, there are a few options that would imply that headers can be fixed. Heres how to really fix them, leave all the above settings unchecked and save the rdl to a local file. Load it up in notepad ( or...