Found what I needed!
The mesh must also have additional vertices data:
* *Matrices weights* : 4 floats to weight bones matrices
( `mesh.setVerticesData(BABYLON.VertexBuffer.MatricesWeightsKind, matricesWeights, false)` )
* *Matrices indices* : 4 floats to index bones matrices
( `mesh.setVerticesData(BABYLON.VertexBuffer.MatricesIndicesKind, floatIndices, false)` )