3) Yes, the manual option allows you to retrieve the connection string any way you want to. You don't have to use the ConnectionManager class at all. (especially the ConnectionManager.SetConnections() method [Wink] ).
I especially not call this method as you say and all work ok (I was thinked that this line cannot have to be supressed
)
4) Yes, the field must belong to the CurrentDataTable to be able to filter on it. So, if you add an additional column to the CurrentDataTable and populate that column, you'll be able to filter/sort on it. But, if you just have a custom field that does not have a backing column in the CurrentDataTable, you will not be able to sort/filter on it.
I don´t watched that I don´t need to use Currentview.table
I called my "_ExtraColumnAdd" method after the fill method and voila! 
Private Sub _ExtraColumnAdd()
'Me.CurrentView.Table.Columns.Add("ExtraColumnName", System.Type.GetType("System.String"), "")
Me.CurrentDataTable.Columns.Add("ExtraColumnName", System.Type.GetType("System.String"), "")
Dim row As DataRow
'For Each row In Me.CurrentView.Table.Rows
For Each row In Me.CurrentDataTable.Rows
'Some stuff to fill the new column here
row("ExtraColumnName") = "Voila!"
Next row
End Sub
later on my form I can use this column like another
It´s the best thing to do about add a new calculated field that can be filtered?Thanks Ben and Trent for all the support to learn all the stuff around Strataframe, you are awesome

pd: Can I post a sample with a routine that recursively read a DB to fill a treeview on the contribution topic to read some feedback on what is wrong and what can I do in a better manner?
its used to create a tree menu like
1 : Module 1
1.1: ABMs
1.1.1: Customers
1.1.2: Employees / etc)
1.2: Configs