I'm a USian and did experience PIA for Vertigo 2006, but with the advantage of having family in Japan through my husband. Even then the process was challenging (the Mods and ticket representatives survived me. I almost didn't make it. lol)!
Peeking around sources and blogs, I'm finding that it might continue to be for fans. Patience and research will help you through the process.
From what I see, you need a Japanese phone number and address. Here is an unofficial post about the process.
I'm assuming the same for e+, and when doing a search found information that indicated that you also need a Japanese phone number. Something about SMS verification being a mandatory step to prove identification.
Given this, please keep in mind that this is not official information from PIA or e+. I strongly recommend that you contact both ticket agencies via the information shared via U2.com. Begin the process now of making contact.
I also suggest you search the internet yourself for resources and experienced fans who have specific insights for you. I would be doing a lot more work to prepare if I was going, but since that's not the case, I'm here to support fans making the trek from outside of Japan if need be.
Please keep us posted about what you find out.
All the best!