I downloaded the trial of CS6 and went through the workflow steps in this video: https://www.video2brain.com/en/lessons/multicamera-improvements
Creating a multicam source sequence and then using it in another sequence for editing does create a nest, unfortunately.
Bit stumped here… So using nests is the only way to use the multicam viewer in Premiere?
In FC7 I don`t remember this being the case. Exported EDL/XML conformed perfectly fine, even when using multicam clips in an edit.