Hi Meursault-2,
Well, I did it but it cost me far more than I mentioned in an earlier post, where I claimed to have solved point 2.
You can see it working at
http://www.olokuti.comCreate a user in "Registrate", add products to your cart, then go to "Blog", then back to Tienda Online (or any other tag, page, etc.)... and you can see that the information is maintained all the way through.
I spent 1 month and a half working on the subject. The reason was also my too basic knowledge of sessions handling (It's far better by now, believe me!). And that is exactly why I use frameworks: for their very first layers (login, sessions, etc.) which have been heavily tested, and have no reasons to be modified from one project to another.
Regarding OSC-WP, I found no help or real solutions on the net. Even commercial products that claimed to handle the issue (exactly as I thought I had at first) were not really integrating both frameworks, and information was lost on certain (in fact very frequent!) conditions.
What I can say is that the solution maintains 2 separated installations of both frameworks (wwwroot/osc and wwwroot/wp) along with their own rewriting rules, and does not mean a big code-rewriting : it's clean, fast (keeps performance as good as it was), and flawless (as far as I know... any bug report greatly appreciated).
However, it is not the kind of "try this line of code" solution, and it could also depend on your own server configuration, security, etc. I am working as an IT freelance consultant. So if your need is professional, feel free to contact me through the mailbox.