Hi, can anyone share their experience of uploading gpx files to a Garmin Montana 610. Not to be confused with the wrist watch, it is a handheld gps device. I have used it for navigating but cannot upload gpx files to it, that I have created using a third party app. I have followed the Garmin website advice and instructions but when I come to upload, my device is not recognised by Garmin, even though it is showing clearly on my desktop. Both the app and my device use open street source mapping, so there is no compatibility issue, what else could be the problem?