ZebraDesigner for XML - ZD620 - multiline variables

<?xml version="1.0" standalone="no"?>

<!DOCTYPE labels SYSTEM "label.dtd">

<labels _FORMAT="E:CBLOCK.ZPL" _QUANTITY="1" _PRINTERNAME="Printer 1" _JOBNAME="LBL101">

<label>

<variable name="shipment_id">23112</variable>

<variable name="truck">Shoestring</variable>

<variable name="job">31998</variable>

<variable name="case">C0005</variable>

<variable name="textblock">  00005

  00016
  00001
  00011

  00021
  00015
  00018
</variable>

</labels>

How do I get the variable textblock to print multiple lines of content?

textblock is defined as multiline

The test print does not print multiline either.