  Solutions of the Vacuum String Field Theory (VSFT) equation of motion
involving matter part are given by projectors, and they represent
nonperturbative solutions (e.g. the sliver) interpreted as D25-branes (or lower
dimensional branes), but they are not mathematically well defined as they have
zero norm. In this work we will use a regularization procedure based on the
cutoff version of Moyal String Field Theory (MSFT), a particular version of
VSFT, and we will see that both the sliver and the butterfly states, in this
regime, have a good mathematical description. In particular they are
exponential functions belonging to $\Sc(\RR^{2Nd})$, the space of Schwartzian
functions equipped with the *-product. Then we prove that if we classify those
regularized solutions with K-theory group built out of the C*-algebra
$\bar{\Sc}(\RR^{2Nd})$ we find exactly the same result obtained considering a
K-theoretic classification of D25-branes in usual string theory, using the
topological K-theory of vector bundles over the D25-brane worldvolume. We then
comment on the meaning of this result and possible physical implications.
