1. If creating an attribute is an inconvenience to you, you can always use an existing one. I prefer to create it because I can name it to something that makes sense to me. Both MV and Portal have a large schema and you can pick an existing attribute
to use.
2. How to get the reference? I showed you a detailed step by step how to get that. This manager is a user and has some properties, right? so any of them can be read using the WF I explained to you. [/manager/DisplayName]. This takes the displayName as string,
which is exactly what the reference is.
3. If you don't want to do any work and just have a plug and play device, then this is not the place to look for it.
4. I am sorry, but I have done lost of work to give you all the help you need (Free of charge, when I make a living with doing this). This is a very classical scenario and either of the options I gave you would take me less then 30 minutes to implemented.
I spent more time with this thread then it would have taken me to implemented it. So did you. I honestly don't see the big deal.
5. If you are not comfortable with making this little effort, then perhaps you should hire an expert. I am available for a very reasonable rate.