The pilot stated that he was utilizing the autopilot and flight director to execute the ILS approach to runway 32. The autopilot was tracking the localizer while the pilot controlled the rate of descent along the glideslope with the pitch command wheel on the autopilot, using the command bars as a steering reference in addition to the raw data glideslope needle on the HSI. All seemed normal, according to the pilot, until the aircraft struck trees about 450 feet above airport elevation two miles short of the runway and came to rest on the localizer centerline. A zero foot ceiling with an eighth mile visibility existed at the airport. During the investigation, it was determined that the 1000A IFCS will not provide vertical steering commands as operated by the pilot, but is driven by the pitch wheel. This is not specifically stated in the POH. The pilot had flown extensively with the 800 series IFCS which will provide the expected steering commands. Extensive damage precluded a functional test of the raw data glideslope needle.