of the structure of PSMCs, the non-trivial information of this computation is actually process-independent, and is contained in the definitions of the parton branchings; the process-dependent part is entirely factorized in the Born matrix element. Thus, one essentially has to perform one set of computations (since typically initial- and final-state branchings are treated differently by the Monte Carlos) per PSMC, in order to be able to match an NLO computation with a parton shower simulation according to the MC@NLO approach. So far, these computations have been carried out for the case of   (see refs. [@Frixione:2002ik; @Frixione:2003ei; @Frixione:2005vw]) and, more recently, for  [@HWpp]. In this paper, we present the first results relevant to the matching with  6.4. We limit ourselves to considering the case of initial-state branchings, and present some sample results for the Drell-Yan process.

This paper is organized as follows. In sect. \[sec:mcatnlo\] we describe the various steps necessary for an MC@NLO matching with , from the definition of the underlying parton-level NLO cross section to the MC@NLO short-distance cross sections used for the generation of hard-subprocess events, to be showered by . We present sample results in sect. \[sec:res\], and we give our conclusions in sect. \[sec:concl\].

MC@NLO\[sec:mcatnlo\]
