Softimage Xsi: enveloppe and shape deformations ?

Hi,

I've just finished envelopping my character around its skeleton, I tried to adjust as best as possible the weighting I now I need to create better deformation at articulations like knees and shoulders.

So I tried to create shapes but had some problems.

How do you use shape deformation in conjunction with enveloppes ? Shapes should be applied before or after envelopping ?


Thanks for your help