Referencing CCDA elements in a custom class

I've created a CCDA schema with from an xsd ad now am trying to reference the CCDA elements in a custom class (process). What is the syntax for referencing my CCDA elements?

I've tried the following

Method OnRequest(pRequest As EnsLib.EDI.XML.Document, Output pResponse As Ens.Response) As %Status
{
// constructing PDQ Request
    set tPDQRequest = ##class(HS.Message.PatientSearchRequest).%New()
    $$$LOGINFO("Starting Process")
    set tPDQRequest.Title=pRequest.GetValueAt("/title")
    $$$LOGINFO("Title: "_tPDQRequest.Title)
    set tPDQRequest.LastName=pRequest.GetValueAt("/recordTarget(1)/patientRole/patient/name(1)/choice(1)/family")

    $$$LOGINFO("LastName: "_tPDQRequest.LastName)

None of my log statements output anything. Any hints would be appreciated.