In a statement on the issue with ForeFront being 32-bit or 64-bit, ForeFront Senior Program Manager Carolyn Liu announced today that the upcoming releases of Microsoft ForeFront Protection for SharePoint 2010 (FPSP) and Microsoft ForeFront Protection for Exchange Server (FPES) 2010 with Service Pack 1 will be native 64-bit. The statement came after questions rose on the 32-bit parts in for instance FPE 2010, while Exchange 2007 and 2010 may only be installed on 64-bit platforms in production environments. This is their intent, as the blog also states that scanning engines not yet available in 32-bit will remain hosted in a seperate process with FPSP and FPE 2010 SP1. SP1 will introduce the possibility to alternate between using 32-bit or 64-bit engines. This way you can make the switch when a 64-bit engine becomes available or switch back to the 32-bit engine when required.