If you're mounting it on top of the 4" post, this fixture might work:
http://www.stoncolighting.com/stonco/library/Catalog/s_area_sphpost.pdf Or are you mounting it to a railing or something that runs horizontally? It seems to me that any trunnion-mount fixture would work in that case. Everyone makes one - like this:
http://www.stoncolighting.com/stonco/library/Catalog/s_hid_pmflood.pdf Drill and tap holes or through-bolt it to the railing to support it, connect it to power with liquid-tite (or cord in some jurisdictions) also via a threaded hole in the railing.
[This message has been edited by stevecheyenne (edited 01-18-2007).]
