Mirror Vertex Groups/Weight Paints

I rigged and weight painted a left arm with a hand and fingers, and have it mirrored on the z axis. all my vertext groups are named after the bones for them (i’m using the blender 2.6 armature and all my groups end in .L) but i can’t get the mirror vertex groups to work. every time i apply or even set the modifier to work in edit mode the right groups are the same as the left, and it doesn’t create any bone.R groups. in fact, the vertex groups stay the same. any help?

i guess that blender has a way to do that. in fact, the options in the weight groups inside object, u have a ‘mirror vertex groups’ option. i usually execute this lines in the script editor:

for vg in bpy.context.object.vertex_groups:
if vg.name[-2:] == ‘.L’:
bpy.context.object.vertex_groups.new(vg.name[:-2] + ‘.R’)

don’t forget to ser the tabs in the second and third line