  Strong-field manipulation of autoionizing states is a crucial aspect of
electronic quantum control. Recent measurements of the attosecond transient
absorption spectrum of helium dressed by a few-cycle visible pulse [Ott et al.,
arXiv:1205.0519[physics.atom-ph] ] provide evidence of novel ultrafast resonant
phenomena, namely, two-photon Rabi oscillations between doubly-excited states
and the inversion of Fano profiles. Here we present the results of accurate
\emph{ab-initio} calculations that agree with these observations and in
addition predict that (i) inversion of Fano profiles is actually periodic in
the coupling laser intensity and (ii) the supposedly dark $2p^2$ {$^1$S} state
also appears in the spectrum. Closer inspection of the experimental data
confirms the latter prediction.
