let's see first the environment ;-)
and the obvious - Garmin's Legend C and MacGPSPro v.6.1.0

Garmin's Legend C and MacGPSBabel

maybe useful - not tested yet: LoadMyTracks
all transfers from the GPSR and to the Legend C run without problems - except the maps :-(
why? - you have to start Windows first on your Mac . . . (VPC 6)