Import the attribute "Manager" from AD to ServiceDesk Failure

My steps:
1. Configuration Wizard> Common Additional Field > Add field > Single-line > Field name:"Manager",Default Value:"undefined" Description:"undefined">Update>Save
2. Configuration Wizard> Active Directory>Import Requesters from Active Directory >Select UDF for import>Check Manager:"manager">Import Now>100% Complete

For the city field, I success by using " l " string for city import from AD attribute.
But for the manager field, I fail by using "manager" for manager import.

Question:
1.I fail on manager attribute.Can we import "manager" attribute from AD and keep it as same as ServiceDesk users?
2.If 1. is possible, then we need to use "manager" as the one who can receive notification email on our workflow. For example,after a requester request an incident, then his or her manager could be noticed via email. How can we implement that?
3.And also, we want the requester's manager can be the approver for a workflow.Is it possible to implement as well?