At the moment my difficult is to have different colour between background map (unmapped)(2)
and islands (1)
using Preset At5 gradient colour with shaded relief
It would be satisfying have unmapped areas in sea colour ...
no problem for islands, default 'hot yellow' may be ok !

Probably it isn't possible 'couse is a preset style,
so i'm trying to do better editing user map,
but, is it possible have shaded relief writing file from user map ?
In reference tutorials i find this



but in reality if find this



it's the same ?
i'll have shaded relief at the end ?

Yes you will.

No - the export raster option that is available when exporting a user map (rather than a project) simply creates a "dummy" raster layer underneath the map. This dummy layer is required for maps that have partial transparency, as AT5 maps only render transparency when vector layers are rendered over raster (this is just a quirk of the AT5 map format).
You can't export shaded relief from a user map because the data required (full 3D model of the project) is not available. You *could* mix vector contents from a user map with a shaded relief raster layer, but to do so you would have to export the shaded relief image (from the contour view right-button menu) and run the IMC raster process yourself with the png and kml files that RM has exported. You would then export your user map as normal, and use the large.at5 and at5.xml files in conjunction with the ShadedRelief folder that you generated earlier. Note that if you have coloured depth areas in your user map, these will likely obscure your shaded relief anyway..

So in summary, you're probably better off exporting shaded relief using a preset style. As for background colour - the issue here is that AT5 does not support transparency in raster layers, so if you don't have a colour then you see a black border. For this reason we use the default Lowrance land colour as a background, but in your case blue might be more appropriate. We'll look at adding an option for this in a future release..