Solution from Klaus:
Must change in tour.xml:
<scene ... skipthumb="true"> ... </scene>
And in vtourskin.xml:
<action name="skin_addthumbs">
copy(thumbwidth, skin_settings.thumbs_width);
copy(thumbheight, skin_settings.thumbs_height);
copy(thumbpadding, skin_settings.thumbs_padding);
copy(thumbcrop, skin_settings.thumbs_crop);
if(device.mobile,
mul(thumbwidth,2);
mul(thumbheight,2);
mul(thumbpadding,2);
);
add(thumbxoffset, thumbwidth, thumbpadding);
mul(thumbxcenter, thumbxoffset, 0.5);
set(thumbcnt,0);
for(set(i,0), i LT scene.count, inc(i),
if(scene[get(i)].skipthumb != true,
txtadd(thumbname,'skin_thumb_',get(thumbcnt));
addlayer(get(thumbname));
copy(layer[get(thumbname)].url, scene[get(i)].thumburl);
set(layer[get(thumbname)].keep, true);
set(layer[get(thumbname)].parent, 'skin_thumbs');
set(layer[get(thumbname)].align, lefttop);
copy(layer[get(thumbname)].crop, thumbcrop);
copy(layer[get(thumbname)].width, thumbwidth);
copy(layer[get(thumbname)].height, thumbheight);
mul(thumbx, thumbcnt, thumbxoffset);
add(thumbx, thumbpadding);
copy(layer[get(thumbname)].x, thumbx);
copy(layer[get(thumbname)].y, thumbpadding);
add(scene[get(i)].thumbx, thumbx, thumbxcenter);
copy(scene[get(i)].thumby, thumbpadding);
set(layer[get(thumbname)].linkedscene, get(scene[get(i)].name) );
set(layer[get(thumbname)].onclick, skin_showthumbs(false); copy(layer[skin_thumbborder].parent, name); loadscene(get(linkedscene), null, MERGE, BLEND(0.5)); );
if(skin_settings.tooltips_thumbs,
set(layer[get(thumbname)].onhover, showtext(get(scene[get(linkedscene)].title),SKIN_TOOLTIPS); );
);
if(skin_settings.thumbs_text,
txtadd(thumbtext, 'skin_thumbtext_', get(i));
addlayer(get(thumbtext));
layer[get(thumbtext)].loadstyle(skin_thumbtext_style);
set(layer[get(thumbtext)].keep, true);
set(layer[get(thumbtext)].parent, get(thumbname));
set(layer[get(thumbtext)].html, get(scene[get(i)].title));
);
inc(thumbcnt);
);
);
mul(thumbbarwidth, thumbxoffset, thumbcnt);
add(thumbbarwidth, thumbpadding);
add(thumbbarheight, thumbpadding, thumbheight);
add(thumbbarheight, thumbpadding);
if (skin_settings.thumbs_scrollindicator,
copy(layer[skin_thumbs_scrollindicator].y, thumbbarheight);
add(thumbbarheight, layer[skin_thumbs_scrollindicator].height);
);
copy(layer[skin_thumbs].height, thumbbarheight);
copy(layer[skin_thumbs].width, thumbbarwidth);
mul(halfheight, thumbbarheight, 0.5);
copy(layer[skin_thumbs_scrollleft].y, halfheight);
copy(layer[skin_thumbs_scrollright].y, halfheight);
</action>