Revit :: Adding Posts To Handrail System

I created a new family to use as posts in my handrail system.  This is for a deck railing.  I'm working on creating a model of the building as it currently stands so I'm able to include a picture of what it actually looks like in real life. 
 
I've also included a screenshot showing the properties window for the handrail (showing what balusters are available) next to the project browswer (showing what families I've got loaded in the file).
 
In the project browser, I've marked with a red arrow the family that I want to use in my handrail.  The ones marked in green are actually listed in the handrail properties window.  So how can I make the Dek Rail Post available to my handrail?
 
I've also included the post family as an attachment.