Hi
The only way to do it is to have a relationship between an AD field and the corresponding field in your other datasource otherwise how does the form know which manager belongs to which employee. There are two ways to achieve this, firstly
1) In my managers table I would have another linked table on the manager employee ID to a daugher table containing all employees linked by key of the manager ID eg
Primary table Daughter Table
Adam, 1 Louise, 4, 1; Amanda, 5, 1; Derek, 6, 1;
Geoff, 2 Alan, 7, 2; Jennifer, 8, 2; Steve, 9, 2;
Arnie, 3 Sharon, 10, 3; Elizabeth, 11, 3; John, 12, 3;
So, if Jennifer filled in the form, the form would know that Jennifer's boss is Geoff, because here data in the daughter table gives Geoffs ID.
Personally I would get the employee ID of the user from AD and then publish the rest of the data from the Daughter and Priamry table to the form so AD would provide the key to the individual and hence their authoriser.
2) Publish in AD each persons authoriser, this way is very simple but fraught with upadating problems and accuracy
There are inherent problems with automatically assigning authorisers in case of sickness or holdiays so what I normally do is provide a drop-down list of all people that could authorise the item so her boss, her bosses boss, and so on. If this is put in a flat table then the drop-down list is presents to the user can be the list of all people that can sign-off. One other benefit of this way is that you can filter the DD List by other criteria. For example,
If I was filling an expense form in for £2,000.00 and my boss could only sign off £1,000 then the DD List would only show my bosses boss and on up.
I hope this helps and if you have any furher questions feel free to ask.
Adam