The Xbox 360 version of Street Fighter x Tekken does not support two-player local co-op when you go online - as is advertised in the game manual.
SFxT features a four-player mode that sees two-on-two fights supported by a tag system.
On PlayStation 3, you're able to go online with a local friend, no doubt sitting on your sofa eating and drinking you out of house and home, and play against two others.
On Xbox 360, you can't.
In response, Capcom US boss Christian Svensson offered a mixed message, as reported by EventHubs.
First, he said a fix will not be offered for a patch: "It will not be patched and apologies for the manual inclusion," he wrote on the Capcom forum. "Seems it was an oversight. The difference has to do with how Xbox Live differs from how it handles online and offline accounts."
Then he attempted to explain what was going on, using information supplied to him from his team.
"According to the team:
"'PS3 version: It is possible to mix and match online and offline players for scramble battles and pair play battles. Two local players can play on the same PS3 using 1 PSN ID, and play against other players online.
"'360 version: It is NOT possible to mix and match online and offline players for scramble battles and pair play battles. So you either have to have all players be offline and local (so 4 players, 1 Xbox) or have all the players be online (4 players, 4 Xboxes).'
"The reason for this difference is because of the architecture differences between gamertags and PSN IDs. I'm not sure of the technical details, but basically it amounts to: Sony made it so you can mix and match online and offline, and Microsoft made it so you can't."
However, as many gamers have pointed out, this explanation makes no sense - Mortal Kombat 9, Gears of War, Halo and Call of Duty can all handle two players on one account on Xbox 360 when gaming online.
Svensson then updated with: "I'm going to be looking into this issue further btw. I'm also a bit confused by the feedback from the team."