Is it possible to extract(as xml) a Maintenance Unit and it's components using extensibility rule?

RobbSalzmann​ , ckattookaran​ , db_pdx​ - Thank you all for your valuable responses.

Robb - I wrote the below code to extract entire maintenance unit without specifying each objects and it is working as expected. Here, I made "isExtractAllItems = True". The code isolates the desired maintenance unit from the extracted XML, reconstructs a minimal XML structure containing just this unit (and its workspace context), and saves the result as a new XML file for backup or migration purposes. And both the methods were tested and both works as expected. 

Thanks everyone for the inputs!
Cheers!

Case Is = ExtenderFunctionType.Unknown, ExtenderFunctionType.ExecuteDataMgmtBusinessRuleStep
					
						
						'Get Configuration Settings
							Dim configSettings As AppServerConfigSettings = AppServerConfig.GetSettings(si)
							'Data Management extract location
							Dim folderPath As String = FileShareFolderHelper.GetDataManagementExportUsernameFolderForApp(si, True, configSettings.FileShareRootFolder,
							 si.AppToken.AppName
							 ) & "\" & DateTime.UtcNow.ToString("yyyyMMdd") & "\Extracts"  'If the directory does not exist create
						If Not Directory.Exists(folderPath) Then Directory.CreateDirectory(folderPath)
							'Full path and file name for extract
							Dim filePath As String = folderPath & "\Dashboards " & DateTime.UtcNow.ToString("yyyyMMdd") & ".xml"
						'If file already exist
						If File.Exists(filePath) Then File.Delete(filePath)
						
							Dim isExtractAllItemsTrue = True
							Dim isExtractUniqueIdsTrue = True 
							Dim xmlOptions As New XmlExtractOptions(isExtractAllItemsTrue, isExtractUniqueIdsTrue) 
							Dim xmlString As String = String.Empty
							Dim maintUnitToExtract As String = "YourMaintenanceUnit"							
							
							
							' extract specified items doesn't seem to work, but we need it
							Dim extractDict As New Dictionary(Of XmlExtractItemPk, Boolean) From {
								{New XmlExtractItemPk(XmlExtractItemType.DashboardMaintUnit, maintUnitToExtract), True}
																								}	
							
							'Execute the Metadata Extract
							Using dbConnFW As DBConnInfo = BRAPi.Database.CreateFrameworkDbConnInfo(si)
								Using dbConnApp As DBConnInfo = BRAPi.Database.CreateApplicationDbConnInfo(si)
									xmlString = XmlExtractController.ExtractXML(dbConnFW, dbConnApp, Nothing, xmlOptions, extractDict, XmlLoadExtractType.ApplicationWorkspaces)
								End Using
							End Using	
							
							Dim xmlDoc As XDocument = XDocument.Parse(xmlString)
							Dim extractedMaintUnitElement As XElement = xmlDoc.Descendants("maintenanceUnit").Where(Function(mu) mu.Attribute("name").Value = maintUnitToExtract).FirstOrDefault()
							
							If extractedMaintUnitElement IsNot Nothing Then
							    Dim workspaceElement = extractedMaintUnitElement.Ancestors("workspace").FirstOrDefault()
							    Dim newWorkspaceElement As New XElement("workspace", workspaceElement.Attributes())
							    newWorkspaceElement.Add(New XElement("maintenanceUnits", extractedMaintUnitElement))
						
							    Dim newXmlDoc As New XDocument(
							        New XElement("OneStreamXF", xmlDoc.Root.Attributes(),
							            New XElement("applicationWorkspacesRoot",
							            	New XElement("workspaces", newWorkspaceElement)
							            )
							        )
							    )
							    newXmlDoc.Save(filePath)
							
							End If		
				End Select