There will be a new WEB server demo (not for the same hardware) that uses the IAR compiler released at the beginning of October. Also there is currently an IAR LPC2000 port in progress, but as yet no release date.
Both of these facts don’t help you now of coarse
The IAR compiler has limited inline assembly capabilities, and has no equivalent to the naked attribute. Both these facts mean that unfortunately ISR’s require assembly file wrappers. These are however very simple. The IAR SAM7 port can be used as an example: