@papaschlum
As an older device, your eTrex Vista HCx would not be fully compatible with unicode maps. See
[Only registered and activated users can see links. Click Here To Register...]. Best stick with non-unicode EU 2014.40 to be safe. I concude from your question that you're using MapSource to compile an image. Sorry to say, MS is not fully compatible with large CN and Topo maps, so better to use MapInstall for them. To answer your question though, if the map is routable anyway [as this one is] that field will be automatically greyed out in MS anyway.