Sunrise Seto exchange tickets possibility

We arrive to Narita at noon and in the evening plan to leave on Sunrise Seto Tokyo to Himeji. However we can use our JR-pass (so practically travel "for free") only for nobi-nobi places. BUT! here goes the puzzle. We can't book these seats in advance because of the time of arrival. And we are afraid that we won't be able to "buy" these seats with our JR-pass because it will be only 3-4 hours before the train - there can be no more free nobi-nobi seats.
We've read on the forums that there is an opportunity to buy tickets at home in advance through West JR call center. And then after arrival to Tokyo - cancel them on Tokyo-station and get a refund (with a small fee). And after that get our cancelled seats for "free" JR-pass tickets.

If somebody did something like that before - could you tell the full procedure?
Is it safe to buy tickets through West JR call center?
Where can we exchange tickets?
Where can we get new ones for our JR-passes?
Is there an possibility that we won't get our cancelled tickets for JR-passes?

Book a night bus from Tokyo to Osaka easier and a lot of operate daily.

"Willer" most fomous for foreigners.
http://willerexpress.com/en/

1) We don't need Osaka, we will go to Himeji
2) We realy want enjoy Sinrise night train

I don't know if this works every time, or what the official policy is. I tried working out this puzzle for friends flying into the Narita and coming to Matsue the next day on the Sunrise Izumo, and everyone I talked to through JR told me it was impossible to book AND use the JR Passes, so I booked them at full price and then mailed the tickets to my friends.
When they arrived, they showed their JR passes with the tickets just in case, and the staff offered to give them a refund. I don't recall the details, but it might have been this process you're describing.

Therefore, it has worked before, but in case it's not the policy to do this, be financially prepared not to have the refund.

Note that you may be charged be a handling fee for doing the refund. The amount depends on when you do the refund (the closer to the departure date, the more expensive) and can range from 330 yen to 30% of the ticket price. Make sure not to purchase the base fare ticket in advance. Just the limited express ticket (including berth fee if you use a berth - as opposed to nobinobi).