Possible Multiplayer fix (for all those players who are stucked in Limited mode) PS3
Alright... I don't know if this is gonna work for you guys but at least is working for me, I discovered this myself after reading that one player entered in multiplayer mode without problems in an alt acc on his ps3... so this what I got after experimenting:
+What do you need?:
-An alt acc in your ps3 with an active PSN acc.
+The fix step by step: It's a little long, so bear it with me.
Alright, first enter in your ALT ACC and go to AC3 from there, when the game loads you will be greeted with the Uplay acc screen in the main menu (to log in or create an acc) IGNORE THIS BY PRESSING SQUARE, then go towards multiplayer... there wait till everything loads and you will see the screen about Uplay, select register and you will see two options: LOG IN and CREATE NEW ACC.
Select LOG IN and put your Uplay ID and password if you already have one, then the multiplayer will start normally. At this point switch back to your MAIN ACC in your PS3 and go to AC3, if everything goes well you will be greeted again by the Uplay acc screen in the main menu (to log in or creat an acc) IGNORE THIS AGAIN BY PRESSING SQUARE then head towards multiplayer, there wait till everything loads and you will see the Uplay registration again, selec register LOG IN and put your Uplay and ID password.
If everything goes well and you manage to see all the things I'm explaining here then you will be able to play AC3 Multiplayer in your main PS3 acc, it works normally cuz I joined almost every type of match in the game, I'm lvl 20 already and I get invitations and I can also invite friends and form groups.
BUT! (yes here's the but) if you restart your PS3 you will have to make this process all over again, also if you try to access Uplay from the main menu of AC3 or from the multiplayer menu, you will likely get an error (at least for me) and you will be forced to make the steps all over again cuz if you try to enter in multiplayer again you will be in Limited Mode once again.
-THEORY-
After studying this problem and the fix I discovered, there's only one possible explanation with this issue... it's not the servers, it's not the internet conection... it's the UPLAY PASSPORT and UPLAY ACC, there's something wrong with that... but as I said, it's just a theory.
-NOTICE-
Remember guys that this fix works for me, so I dunno if this will work with everyone with the Limited Mode problem... I'm just happy that I can finally play the multiplayer and good thing is that you don't need to access Uplay ingame because you can buy stuff directly from your Uplay page in the webiste, so if this works please post your results and if it doesn't... then post as well and we might try to work on it, if Ubisoft doesn't give us a fix or explanations, then the rest is in our hands and I'm not going to stay with my arms crossed.