This question really belongs in the LabVIEW board and not Instrument Control.
To answer it though, when you say block diagram functions, I'm assuming that you mean the functions palette. Unless you save to specific locations, VIs that you create are not automatically added to any of the palettes. You can use the Select a VI.. option and then browse to it. If you save the VI or llb to the user.lib folder or instr.lib folder, then they will appear on the palette. You can also customize the palette to add VIs or llb in any folder you choose. Go to Tools>Advanced>Edit Palette Set.
