Hi
I have seen one similar setup with an ISP owned 525 hanging off of an ISP router where the company had 15 IP addresses that were non-contiguous to the address on the outside interface (infact the outside interface had a 30 bit mask so it basically had one address for the outside interface and the other for the ISP router). All they appeared to have to do to use their public IP addresses was to statically map them to their servers, the default gateway remained the same. Unfortunately I never managed to get a glimpse of the ISP router config, but I assume that the non-contigous addresses were either routed to the outside address of the pix, or that router had a secondary IP address configured and just routed those IP addresses out towards the Pix's e0 in order for the Pix to pick them up. The ISP certainly didn't have anything clever configured on the Pix pertaining to the extra addresses
Hope that helps
Kev
