How to add skins to ships?

I'm just trying to use different skins for the Soldati class destroyer in the WDAD mod (I think it is the same one as in OM), but I can't make them work.

I've added a few TGA files for the Soldati I found in a SH3 download, renamed accordingly as I've seen in other similar ships, modified the Roster entry with dates and frequencies, but no success at all. I also tried to convert the textures to DDS format, but that didn't work.

I'd like to get the Soldati's show different liveries, because it is the only Italian destroyer I can use to escort convoys in the Mediterranean, and it's boring to see them always with the same look. I've tried to use the search, but I didn't get many useful results.

Any ideas?

Cheers