Marco
ME will confirm any components back to ECC that are directly consumed on the current SFC (and not inside a subassembly of the SFC as would be done during manufacture of the subassembly in ME).
Only those components which are defined as not backflushed in ERP (i.e. the "Backflush in ERP" flag is NOT set in Material Maintenance) will be confirmed. Bear in mind Evgeniy's point about the configuration of the collaboration also, with regard to sending onlyNonBackflushed or noneIfBackflushed.
Stuart