how can i create an autoincrement field via a connection using the jet 3.5 database engine?

this is my connection string
Code:
objDB.ActiveConnection = "Provider=Microsoft.Jet.OLEDB.3.51;Data Source=" & strFileName
i've found information about jet 4.0 and then setting 'autoincrement' on the properties,

but how can i do this in jet 3.5??