Found this solution in another thread that seems to work:
In UE Attachment > Entered Value
Paste:
<?php echo $WA_DFP_UploadStatus["WA_UploadResult1"]["serverDirectory"]; ?><?php echo $WA_DFP_UploadStatus["WA_UploadResult1"]["serverFileName"]; ?>
Is that an option in the wizard, or an alternative workaround?