How to copy envelope values to another?

[JQuacker]

Alright, i've finally got one envelope (in this case, the one over the left arm forearm) value's set. How can i copy it to work with the opposite side (i.e., the right arm)? Do I have to manually set all the verts on the right arm?

[Wolfe]

In XSI you use the wirror weights tool under the envelope menu, after setting a symmetry template.