Hi Joe.

Set Up Document Transmittal Help has a section Keyword Substitution with the instructions on how to add certain keywords within the subject or body text content of the email. Here is the extract:

You can add certain keywords within the subject or body text content of the email. For example in the Body Text of an invoice, you might enter: 

"Invoice # {TranID} - {CustPONo} is completed and now due for payment. The invoice amount of ${TranAmt} is due by {DueDate}." 

The curly braces ({}) indicate that a substitution needs to take place. If you enter a valid keyword substitution, the substitution happens. Otherwise, the keyword is ignored and is transmitted with the email. The following lists the valid keyword substitutions that are available for Customer Statements:

Customer Statement
{ContactName}  {AgeCat1Bal}
{CustName} {AgeCat2Bal}
{CustUserFld1} {AgeCat3Bal}
{CustUserFld2} {AgeCat4Bal}
{CustUserFld3} {AgeCurntBal}
{CustUserFld4} {AgeInvcAmt}

Thanks that did it.