No worries, I must point out my experience with Airports other than the large open space variety with toothpaste tubes out front ready for takeoff is not that great.

But one thing that is important is that once you have configured the WAN port of the airport for staticIP and loaded the appropriate supplied addresses then sometimes the powering sequence between the modem and router is important, as the Surfboard can get a bit picky/cranky about how it collects the MAC address of the attached device (Airport in this case).

Cheers
Cyril