Printing Styled Text

I am trying to print a series of letters in a textarea with styled text.

I have a routine that replaces all instances of certain text with customer names, address, etc.

The code looks something like this:

//SUBROUTINE ReplaceAllStyledText(SourceText as TextArea, TextToFind as string, ReplacementText as string)
// how often is the TextToFind in the SourceText?
dim i as integer = InStr( SourceText.text, TextToFind )

// iterate over the text until all occurences have been replaced
while i > 0
SourceText.SelStart = i-1
SourceText.SelLength = Len( TextToFind )
SourceText.SelText = ReplacementText
i = InStr( SourceText.text, TextToFind )

      s = WordProcessor_container1.TextArea1.StyledText  //Save the original text to be reused
WordProcessor_container1.ReplaceAllStyledText(WordProcessor_container1.TextArea1,"<firstname>",fname)  // pass the TextArea into the method, not just the text of it

      Dim stp As StyledTextPrinter
      Dim g As Graphics
      Dim ps As New PrinterSetup
      Dim pageWidth, pageHeight As Integer
      If PageSetup <> "" Then //PageSetup contains properties
        // open Print dialog with Page Setup properties
        g=OpenPrinterDialog //open dg w/o Page Setup properties
        pageWidth=72*7.5 //default width and height
      End If
      If g <> Nil Then //user didn’t cancel Print dialog
        Do Until stp.EOF
          stp.drawBlock 36,36,pageHeight-48
          If Not stp.eof Then //is there text remaining to print?
          End If
      End If
      WordProcessor_container1.TextArea1.StyledText = s  //Replace the original text for the next letter to print

All works well until I try to do this in a loop of records. The textarea does not update and so the same data stays merged in the letter. Not sure how to let the UI update so the textarea returns to the original text so it can be reformatted for the next customer.

Is there a way to not use the textarea but instead place the styled text into a variable, replace the desired text with data, and then print that?