I am not sure if I understand your question. I need more information. I think that you are saying that you need to have a workstation mapped to a shared drive on a server so that a service running on the workstation can use it regardless of a user being logged on. This is possible. Simply map the drive, configure the service to start automatically, and to use the mapped drive. This connection should remain regardless of a local user being present or not.
It would be simpler however to just use the UNC of the resource on the server, but again, I am guessing about your application. Please provide more details.