Do you have to use a crusting buttercream in order to get a fondant ribbon to stay in the middle of each tier? I'm afraid a butter-based buttercream won't hold up the fondant. Working on my first wedding cake....thanks!!
I've done it before, and never use crusting buttercreams....
Just make sure its nice and chilled before putting it on, otherwise it'll squish into the buttercream too much!
Rather than icing you could lightly brush the fondant ribbon w/water before applying it to the b'cream.