Re: new structure page not visible at module
Can you please post this as a regression in the bug tracker at http://dev.tiki.org/Make+a+wish
, and create a show.tiki.org instance there associated with your bug report with tiki12, so that some developers can have a look at that.
In the mean time, you might get what permissions or whatever are needed in Tiki12, if that's the case (I upgradede many sites, where I use wiki structures, and didn't get that issue, so maybe some permission related to structures that was not properly set in the structure homepage, that is required in Tiki12 ? (just a guess)