If you mean that the table serves as both logical fact and dimension you can simply use the same physical table in multiple Logical Table Sources, or you can Alias it in the Physical layer in order to create two versions to reference. Both approaches have their merits; the former can sometimes lead to more efficient SQL.
I agreee with rmoff and would just add:
A non-aliased approach is better in terms of SQL for the case of role-playing flat tables. You can later-on always alias off additional instances, but for the sake of SQL execution I would heavily suggest keeping the core fact and dim LTS on the same physical table object.