Series volume field dependent Punctuation

Hello there!

I’m new to EndNote and I’m trying to edit and output style to adjust to my University standards…

My problem is that when a book belongs to a series it should be (Series Title Series Volume). This works nicely with the sequence 

Author, Title |(Series Title Series Volume)|, Place Published Year, Edition|, vol. Volume|.

But when the Series Volume is blank, the closing ) misteriously dissapears. I’ve tried different combinations with the | and ◊, but can’t get it right. So as a temporal patch I added the closing ) to the Series Title when it has no number. But that’s destined to not work well with other styles. Do you have any clues?

Thanks so much!