Surround Pan Envelopes
You can automate the surround panning for individual clips using envelopes. This is slightly different from using regular volume and pan envelopes.
Internally, there is a single surround pan envelope where each envelope point contains a complete surround state (left-right position, front-rear position, and LFE amount).
When you look at the envelope for a clip, you can choose to view either the left-right, front-rear, or the LFE curve.
When setting envelope points for either one of the envelope types, that point is automatically added to the other envelope types at the same position in the clip.