Can't create a Vendor Comment using the writeattach API from AP10.1.

I am attempting to programmatically create a vendor comment in the FORM_OnAfterTransaction(data) event of AP10.1.  On pages 105-106 of the Lawson Design Studio User Guide version 10 (LDSUG_10.0.9.0_UWA.pdf) there is an example for exactly what I want to do.  The problem is that it's not a working example.  It looks like it's creating an Invoice comment, not a Vendor comment because it references Invoice data fields that aren't available to AP10.  Here is their example:

function FORM_OnAfterTransaction(data)
{
 // was transaction successful?
 if (formState.agsError) return;

 // grab the value for the select box
 var vList = lawForm.getFormValue("select12");
 if (vList != "None")
 addComment(vList);
}

function addComment(vList)
{

//Case for the four options
 var vAudt
 switch (vList)
 {
 case "All":
 vAudt="A";
 break;
 case "Report":
 vAudt="D";
 break;
 case "Note":
 vAudt="N";
 break;
 case "Check":
 vAudt="C";
 break;
 }
 // set variables from the form to use in API
 var vComm=lawForm.getFormValue("textarea1");
 vCompany = lawForm.getDataValue("API-COMPANY");
 vVendor = lawForm.getDataValue("API-VENDOR");
 var vInvoice=lawForm.getFormValue("text12");
 vTitle = portalWnd.oUserProfile.getAttribute("lawsonusername");

 // build the API call for the writeattach cgi
 s = portalWnd.WRITEATTACHPath + "?_OUT=XML&_PDL=" + strPDL;
 s += "&_FN=APINVOICE&_IN=APISET1&K1=" + vCompany;
 s += "&K2=" + vVendor;
 s += "&K3=" + vInvoice;
 s += "&K4=000&K5=0000&_ATYP=C&_AUDT=" + vAudt;
 s += "&_USCH=none&_DATA=TRUE&_OPM=M&_ECODE=FALSE&_ANAM=" + vTitle;
 s += "&_ATXT=" + vComm;

 // send API to the server
 portalWnd.httpRequest(s);

 // Reset the Textarea and set the select to None
 var space="";
 lawForm.setFormValue("textarea1","");
 lawForm.setFormValue("select12","None");
}

You can see it gets data from API-COMPANY and API-VENDOR which are not AP10 data fields.  Here is what I am doing (have some debugging code in there for now):

Here is my call to the addVendorComment function below:

addVendorComment(vendorCompany,sVendorfld,"","D","OFAC","OFAC CHECK COMPLETED PAYEE INFO NOT A MATCH TO WLE.");

function addVendorComment(vendorCompany,vendor,locationCode,commentType,commentTitle,comment){

 /* This function will add a vendor comment. */

 /* build the API call for the writeattach cgi */
 s = portalWnd.WRITEATTACHPath + "?_OUT=XML&_PDL=" + strPDL;
 s += "&_FN=APCOMMENTS&_IN=APCSET1";
 s += "&K1=V";
 s += "&K2=" + vendorCompany;
 s += "&K3=" + vendor;
 s += "&K4=" + locationCode;
 s += "&K5=0000&_ATYP=C&_AUDT=" + commentType;
 s += "&_USCH=none&_DATA=TRUE&_OPM=M&_ECODE=TRUE";
 s += "&_ANAM=" + commentTitle;
 s += "&_ATXT=" + comment;

 alert("s=" + s);  // For debugging
 
 /* send API to the server */
 var addCmnt = portalWnd.httpRequest(s);
 alert("HTTP Request complete");  // For debugging

 if (!addCmnt || addCmnt.status)
 {
    // error retrieving file: display message
    var msg="Error adding " + commentTitle + " comment.";
    if (addCmnt)
       msg+=("\n"+portalWnd.getHttpStatusMsg(addCmnt.status));
    portalWnd.cmnDlg.messageBox(msg,"ok","stop",window);
    return;
 }

 alert("Checking error message"); // For debugging
 var addCmntErrMsg = addCmnt.selectSingleNode("//ErrMsg").text;
 alert("Error message: " + addCmntErrMsg); // For debugging

}

The last "alert" displays "Error message: Invalid value for User Defined Type: _AUDT=(D)."

I opened an incident with Lawson support and pointed out the example in their documentation doesn't work and is incorrect but they told me I would need to contact professional services since it was a customization.  Apparently they don't care that their documentation is wrong.

Has anyone been able to successfully generate a vendor comment programmatically or can you see any obvious errors with my code?

Thanks,
Randy