Lie maps on alternative rings preserving idempotents

Let $\Re$ and $\Re'$ unital $2$,$3$-torsion free alternative rings and $\varphi: \Re \rightarrow \Re'$ be a surjective Lie multiplicative map that preserves idempotents. Assume that $\Re$ has a nontrivial idempotents. Under certain assumptions on $\Re$, we prove that $\varphi$ is of the form $\psi + \tau$, where $\psi$ is either an isomorphism or the negative of an anti-isomorphism of $\Re$ onto $\Re'$ and $\tau$ is an additive mapping of $\Re$ into the centre of $\Re'$ which maps commutators into zero.