Thanks for your help Nupsi,
Using cube-hotspots is a good 'hack'. I didn't think about it!
It can actually work, but not in my virtual tour.
Each scene has some specific data, layers and hotspots. Something like
<scene name="scene1">
<data name="intro">Some text</data>
<layer name=""map" />
<hotspot name="feature_1" />
</scene>
It's SO convenient put all those things inside <scene> tags!
This way when a new scene loads, it shows the data "intro'. And the map shows that particular scene map. And so on...
It's not worth it to edit the whole virtual tour programming to don't use <scene> tags. It would take a week or so :-)
I was hoping to find a feature that I didn't know until now, like 'loadcene" with IGNOREIMAGE flag, which loads a new scene ignoring <image> parameters, and hence keeping the previous scene tiles.
Don't bother to look, it doesn't exists as far as I know :-) But it would be soooooo coooooool for me!
Thank you anyway!!!