GPO is programmed to use cc1 as volume (among other things, such as timbre, etc.), so if you are reaching for the mod wheel (cc1) hoping for modulation, or vibrato, you won\'t get it.
There is no separate, built in \'vibrato\' controller for GPO. On the other hand, GPO\'s brilliant use of cc1 is the genius behind the wonderful expressiveness possible with this amazing little library.
My Korg Triton Studio has this \"joystick\" which Cubase SX automatically associates with modulation (volume) and pitch changes (not vibrato, but pitch). I\'m still getting used to \"kicking the mod wheel\" at the beginning of a track to record a modulation change (so that it can later be edited for setting initial volume of the track).