Well, according to grigri, the well known c++ coder, they are part of the treeview control, meaning, we can't modfiy them at all

I'm not one to give up easily, but I have to admit, I do believe him in full, mainly because he is as smart as he is, but also because I've searched every
dll file, every exe, everything. I've seen every icon, every bitmap, every gif, every string table, everything, and nowhere can I find anything that even comes close to those + and - symbols
So, unless something comes around from another source, I have to back explicit and meth up on this one, just isn't gonna happen
There are other things you can do to that treeview though, couple of tuts floating around at my site covering it, lot's of stuff you can do actually, makes for a big difference
