I don't know if this can be usefull... but if somebody thought thta well.. I'm posting what i discover while trying to upload a mesh in SL.
ATTENTION: in all those tests the mesh was perfectly rigged in software - not in SL
MAC 10.6.8
C4D 12 and 11 export in COLLADA 1.4.1 --> unable to upload a rigged mesh (the calculate weight and fee disappear). Orientation of the model 90 degree off skeleton (only in world, not in software)
BLENDER 2.49 --> model 90 degree off skeleton (only in world, not in software)
BLENDER 2.59 --> unable to upload a rigged mesh (the calculate weight and fee disappear).
MAYA 2010 --> unable to upload a rigged mesh (the calculate weight and fee disappear).
MAYA 2012 --> unable to export proprely in COLLADA
I have no idea, i tryied many times building different models. All faces was perfectly facing normal, rigging was working perfectly in software.