Noether normalization tells us that a finitely generated $k$-algebra is an integral extension of a polynomial algebra over the field $k$.

My question is whether this still holds if we replace the field $k$ by a more general ring.

Question: Let $R$ be a commutative ring, and let $A$ be a finitely generated $R$-algebra which is flat over $R$. Are there $R$-algebraically independent elements $x_1,\dots, x_m\in A$ such that $A$ is integral over $R[x_1,\dots, x_m]$?

EDIT: According to the fact that the general question was already asked, and also to the answers already given, I should change the question to the case, I am really interested in:

What is the answer in the case that $R$ is a local $k$-algebra of dimension zero over some field $k$?
(So $R$ is nearly a field, but not reduced).