Struggling with Avastar

Hi everyone,

I have been struggling for a month or so now, trying to create some shoes. Apparently I can save and upload them properly using Blender save, but not Avastar, as it flips normals. Any clues?
See the pictures below.

 Here is my file, proper normals

 My file loaded as Blender file, after saving ( but no weights), in red, and in white, as Avastar weighted

 This is how it appears when saved with Avastar dae, and sometimes the file is not even saved,

scarpa 3 ott avast is a file saved in Avastar, exported in dae - can't be read as such

this is how I save.
I guess there is something in my file which makes the program crazy, no idea what it is .