I'll be traveling on an award ticket on ANA in a few days. Is there any way I can get a few miles into my ANA account by purchasing something on board, in the lounge, duty free, etc.? I vaguely recall this as an option from a previous trip (it was a couple years ago) but i don't remember the details.

The reason to keep a few miles in my account is to ensure continued access to *A searches using their online tool. I do have a few miles in there now, but those will probably expire soon. I figure if I can do something easy (buy something small, etc.) to maintain account activity (other than flying on a paid ticket ), I might as well...

Thanks.