The EPSG 1612 reference on the datum is for a geographic/datum transformation, ED 50 to WGS 1984 (23). The software this data comes from must be "early-binding." That is, each GCS/datum has a transformation linked to it. ArcGIS is "late-binding." Data is tagged with a neutral coordinate system definition. When you need to transform it to another coordinate systems, then you pick a particular transformation. So define the data with ED 1950 UTM zone 32N (north). If you need to convert it to WGS84, use ED_1950_To_WGS_1985_23.