VBA to select and copy specific reference files (MicroStation 2004)

In respect to Set oAttachments = ActiveModelReference.Attachments, how do you select a specific reference file with this command? I want to copy/use the clipping properties of an existing reference file. Also at a later date, I would like to pick specific reference files to turn on or off levels. Looking through all the threads, I can only find mass reference file manipulation. The code for clipping to a shape looks quite complicated.

 Thank you