Can't filter community query by custom property

Question

I'm trying to search for a community through the objectManager based on a custom property value (part of a LoginPEI that redirects the user on login to a personalized community).  The Query() call is failing with the following exception:
    ParseQueryFilter error on clause #0
    (0x80070057) Invalid property ID specified (0xc8)
where 0xc8 is the ID of the property I'm filtering by.
The same code works correctly if I filter by PT_PROPIDS.PT_PROPID_NAME instead, making me think it's something about either that property in particular, or just filtering managed objects by extended props in general.   I've confirmed that the property has been added to the community object through the Global Object Property tool.
Code shown below (and, yes, I'm aware that the results if there are more than one matching object are undefined).  Any advice appreciated.
Thanks,
Pete
    private int lookupObjectBySingleProperty(IPTSession session, int classId, int propertyId, Object value) {
      IPTObjectManager objectManager = session.GetObjectManagers(classId);
      Object[][] filter = {
                            new Object[] { propertyId },
                            new Object[] { PT_FILTEROPS.PT_FILTEROP_EQ },
                            new Object[] { value }
      IPTQueryResult results = objectManager.Query(
        PT_PROPIDS.PT_PROPID_OBJECTID, //Property properties
        -1, // search all folders -- might want to restrict this later
        PT_PROPIDS.PT_PROPID_OBJECTID, //sort
        0, // start at first result
        -1, // return all results
        filter); // filter
      if (results.RowCount() == 0) {
        return -1;
      return results.ItemAsInt(0, PT_PROPIDS PT_PROPID_OBJECTID);

Answer 1

can you try filter this way:
var sURI = 'http://<host>:<port>/sap/opu/odata/sap/ZTESTODATA_SRV/';
  oModel = new sap.ui.model.odata.ODataModel(sURI, false),
  sap.ui.getCore().setModel(oModel);
  var sRead = "/pdfset(customer='" + oTF.getValue() + "')"  ;
oModel.read( sRead, null, null, true, function(oData, oResponse){
  var pdfURL = oData.url;