This calls for changing core wrapper funtionality by way of template owerrides. This has the sideeffect of passing session info to every other wrapped pages as well, and on our site I found at least 3 pages where this lead to error.
The right solution to this problem is - of course - to create a new module / componet to do the wrapping and pass sessioninfo.
To be continued!
Links on retriewing path to stylesheet:
