I am also interested in the IAR 5.0/FreeRTOS combination. Presumably there is a way to enter an OSEK ORTI file into the IAR configuration using the IAR GUI. The file structure for an ORTI file is found in http://portal.osek-vdx.org/files/pdf/specs/orti-a-22.pdf
It’s not trivial but a few days perhaps to figure out and get such a file to work from scratch. I don’t know what ORTI version is compatible with IAR’s IDE.