12 days is pretty early to expect your beer to be fully conditioned/carbonated. As you're finding, it's usually drinkable at two weeks, but much better after 3 or 4.
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FYI, what many homebrewers describe as "secondary fermentation" is a rather incorrect term and can cause confusion sometimes. You are not inducing a second fermentation by racking your beer to another fermenter, you are just moving it away from the trub. More correct terms for the "secondary" are "clearing tank" or "bright tank," and what happens there is "conditioning" or "clearing" rather than "secondary fermentation."
Also, there is still a ton of suspended yeast, even in perfectly clear homebrew (unless it's been filtered), so carbonation shouldn't be a problem.
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