Type variables within type quasiquotes

Hi,

Contrary to what's stated in GHC's 6.6 user's guide
(http://www.haskell.org/ghc/docs/6.6/html/users_guide/template-haskell.html
) type quasiquotes seem to work just fine when type variables are not
used (i.e. things such as [t| Bool |]).

But unfortunately GHC complains when I make use of type variables

[t| Maybe a |] leads to "Not in scope: type variable `a' "

Am I doing something wrong or did I run into one of the reasons why
the guide says that type quasi-quotes are not implemented?

Thanks in advance,

Alfonso Acosta