According to 19.1.1 in the MCF54455 Reference Manual (Rev 2) the part has 6 chip selects (FB_CS[5:0]) and it provides details on the six chip-select address registers and six chip-select mask registers in 19.3.1 and 19.3.2 respectively. However, I can't find pin numbers for FB_CS4 and FB_CS5.
In the MCF5445x Microprocessor Data Sheet I can only find reference to FB_CS[3:0] so does it in fact only have 4 chip-selects or are FB_CS4 and FB_CS5 multiplexed with some other pins?