  After a review of how Boson Fock space (of arbitrary multiplicity) may be
approximated by a countable Hilbert-space tensor product (known as toy Fock
space) it is shown that vacuum-adapted multiple quantum Wiener integrals of
bounded operators may be expressed as limits of sums of operators defined on
this toy space, with strong convergence on the exponential domain. The
vacuum-adapted quantum Ito product formula is derived with the aid of this
approximation and a brief pointer is given towards the unbounded case.
