How is a correspondence variant linked to a transaction?

Hello, in transaction FB60 when i click on Environment -> Correspondence, i get a popup in which Open item list is written.

When i launch ob78(allocate program for automatic correspondence), i see that the description for SAP08 is 'Open item list'.

What is the relation between FB60 and SAP08.How is it linked?

does anyone have some good documentation on this.thx.

Edited by: Antish Awootar on Sep 8, 2009 1:52 PM