  We show that the space of trace-class operators on a Hilbert module over a
commutative C*-algebra, as defined and studied in earlier work of Stern and van
Suijlekom (Journal of Functional Analysis, 2021), is completely isometrically
isomorphic to a Haagerup tensor product of the module with its
operator-theoretic adjoint. This generalises a well-known property of Hilbert
spaces. In the course of proving this, we also obtain a new proof of a result
of Stern-van Suijlekom concerning the equivalence between two definitions of
trace-class operators on Hilbert modules.
