I think you updated GE to v4.0.11.0, now it gives option to install to Basecamp. Nice it works now
Unlock code is necessary or map wont be unlocked in nuvi.

v4.0.11.0 version includes the following changes:
•Added improved notifications around ANT Stick use.
•Added more installation options to map reinstalls.
•Added device specific guidance for adding devices to Express.