Well, that wasn't a good idea from the start, as instance name isn't a
reliable identification (you can assign two identical names to different
instances and that will compile, while the second instance will not
be available). What I usually do in such case is: I prepare the class with
the fields it should have, give it to designer and explain hot to link their
library items to that class, and then when I compile, I use my own version
of that class with the functionality added, this way we (me and designer)
can work on the same class and I don't have problems using it in my project.
Ah, important to note, this approach requires that the designer turn off the
"automatically declare stage instances" in publish settings.
