How do I include a URL and the Document Name using Azure's Cognitive Search and Azure OpenAI

Question

When calling Azure's OpenAI with Cognitive Search I am requesting for the UrlField Name in the Field Mapping which is returning null. I have tested this in the Azure Open AI Chat Playground and this same field (metadata_storage_path) is returning a URL. Am I doing something wrong?

openAiClient = new OpenAIClient(
          new Uri(_OpenAIEndPoint),
          new AzureKeyCredential(_OpenAIAPIKey));

            chatCompletionOptions = new ChatCompletionsOptions
            {
                Messages = { new ChatMessage(ChatRole.System, _PrimingPromptForOpenAI) },
                
                AzureExtensionsOptions = new AzureChatExtensionsOptions()
                {
                    Extensions =
                    
                           {
                            new AzureCognitiveSearchChatExtensionConfiguration()
                            {
                                SearchEndpoint = new Uri(_CognitiveSearchURL),
                                SearchKey = new AzureKeyCredential(_AzureKeyCredential),
                                IndexName = _AzureSearchIndex,
                                SemanticConfiguration = _SemanticConfig,
                                FieldMappingOptions = new AzureCognitiveSearchIndexFieldMappingOptions {UrlFieldName = "metadata_storage_path"}
                                                              
                                
                              
                               
                            }
                          },


                }
            };