I applied the GOOGLEEARTH twosided in an *older* version of the Collada14 exporter and - for easy programming - applied it to all.
[
pasteall.org] -the collada.py
[
pasteall.org] -the translator.py
You would need to find the relevant changes - search for GoogleEarth in Collada.py and work backward from there to copy just the related changes. I had other things in there for UV triangle texture bug fixes and scene-graph transforms with repetitive geometry.
(The current version exporter doesn't work on my data - it doesn't display in GoogleEarth - so I'm staying for now with the older version.)