loadxml via javascript. BLEND not waiting for pano to be downloaded. Black screen in between.

var xlml = "<krpano><include url='photospheresDisplay/presets.xml' /><view hlookat='0' vlookat='0' fov='110.0' fovmin='1.0' fovmax='179.0' fisheye='1.3' maxpixelzoom='1.0'/><image><sphere url='"+baseMediaDirectory+newfile+"'/></image></krpano>"; var krpanoThetaGD = document.getElementById("pano_ThetaGD"); krpanoThetaGD.call("loadxml(" + xlml+ ",null,KEEPALL,BLEND(0.5))");

This is javascript code. my presets.xml define a fisheye value of 1.3 so the 360 shows as a sphere.
The div that contains the embed has a background-color: transparent; parameter
The original embedpano (via javascript happens on first pano image, then keeps it for other ones, until it is removed), has a wmode:"transparent" parameter. html5 only, no flash.

So the space surrounding the sphere is transparent.
But when I load a new sphere via the code above, I get a black flash in the background before or while the new pano image appears.
And as the load of the new image takes about 1s, the BLEND often happens from previous image to nothing (transparent) then new image comes suddenly, unless images are already cached.

As a side note I wonder if it possible via javascript to preload the next(s) image in advance?

Sorry I can't give a link. This is a work in progress that I can show.