I too would like to see if Gamesplanet can clear this up, perhaps by asking their Capcom representative. Looking at Steam database entries, I get the impression that this could be unplayable in Japan.

The following flags are set:
ReleaseStateOverride released
ReleaseStateOverrideCountries JP
releasestateoverrideinverse Yes

The first two flags mean that the normal release state has been superceded for Japan. And has been set to "Released" for Japan. However, the third flag reverses this setting. Meaning that it is actually "Unreleased" for Japan.

The problem is, the Steam database cannot distinguish between the specific regional versions. That is, it also shows the same flags when viewing the information via the Japanese version of the game.

If this can be cleared up, I'll happily buy. But I don't want to risk activating a key that is stuck in a permanent unreleased state (making it difficult to get a refund).