Oh, well um this one isn't automatic so I would have 2 go to the new forum, see what items you have and transfer it over to this one. I'm not doing the posts or points from the new to the old, cause there really is no point ._. Plus that might get annoying because of people saying "I just bought this on the new forum, can I transfer it to this one."
However I might just give you like 1 pokemon you can have like "once you join the forum, pick one pokemon in a list of xx" stay active and it will evolve to its next stage, or something like that but that might be to much work. I got ideas, but they are always to much work ._.