Installing Beta Software with a Mac?

Installing Beta Software with a Mac?
I'm installing Garmin BETA software on a Mac in that way:

* Rename the .exe into .zip
* unpack it with the Mac-Software "GUI Tar" (http://www.edenwaith.com/products/guitar
 )
* Find the file "gupdate.gcd" in the (extracted) folder structure in the the folder "Garmin"
* copy "gupdate.gcd" to the same folder "Garmin" on the device (NOT on the additional memorycard)
* Rebootpermalink

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