UML Modeling for Class calling another class in Class Diagram and Sequence

In my application, business delegate is calling Session Facade through business interface. Session Facade is implementing business interface which includes my application business processes.

In my class diagram, I am showing business delegate, business interface and Session Facade.

What kind of relationship should be shown between

1. business delegate and business interface

2. business delegate and Sesion Facade

I am not very sure wthether relationship mentioned above are really need to show.

What should be calling sequence in sequence diagram. Do I really need to show business interface in callling sequence of sequence diagram or I can show business delegate is calling directly to Session Facade.

Thanks

San

[776 byte] By [San4Ua] at [2007-10-2 23:40:53]