Deprecated. See SITE_EMAIL_SEND. This method can be used to email a document to someone who is linked to an Order, Invoice, or Opportunity created within the session. Typically it is used to email someone who just made an order.  
  ApplySystemTemplate Text (1) Y/N. Default N. If set to 'Y' it will add your standard email template
  Document Numeric Mandatory.  Make sure it is marked as Public=Y
  Object Numeric Mandatory. Must be either 43 (Order), or 5 (Invoice)
  ObjectContext Numeric Mandatory. Id of Order or Invoice
  SaveEmail Text (1) Y/N. Default Y.
  SendAttachments Text (1) Y/N. Default N. If set to 'Y' add all the attachmnts on the document to the email
  CUSTOM PARAMETERS TYPE Text (?) There is a mechanism to be able to adjust the text of the document in a flexible way. Within the document place the text [[]] and pass the appropriate value. For example, if want to put a person's surname you could have in the document [[CustomValue.Surname]] and pass 'CustomValue.Surname=Jones'